what are the type of literature review

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Systematic Reviews

• Types of Literature Reviews

What Makes a Systematic Review Different from Other Types of Reviews?

• Planning Your Systematic Review
• Database Searching
• Creating the Search
• Search Filters and Hedges
• Grey Literature
• Managing and Appraising Results
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Reproduced from Grant, M. J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91–108. doi:10.1111/j.1471-1842.2009.00848.x

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Literature Review: Types of literature reviews

• Traditional or narrative literature reviews
• Scoping Reviews
• Systematic literature reviews
• Annotated bibliography
• Keeping up to date with literature
• Finding a thesis
• Evaluating sources and critical appraisal of literature
• Managing and analysing your literature
• Further reading and resources

Types of literature reviews

The type of literature review you write will depend on your discipline and whether you are a researcher writing your PhD, publishing a study in a journal or completing an assessment task in your undergraduate study.

A literature review for a subject in an undergraduate degree will not be as comprehensive as the literature review required for a PhD thesis.

An undergraduate literature review may be in the form of an annotated bibliography or a narrative review of a small selection of literature, for example ten relevant articles. If you are asked to write a literature review, and you are an undergraduate student, be guided by your subject coordinator or lecturer.

The common types of literature reviews will be explained in the pages of this section.

• Narrative or traditional literature reviews
• Critically Appraised Topic (CAT)
• Scoping reviews
• Annotated bibliographies

These are not the only types of reviews of literature that can be conducted. Often the term "review" and "literature" can be confusing and used in the wrong context. Grant and Booth (2009) attempt to clear up this confusion by discussing 14 review types and the associated methodology, and advantages and disadvantages associated with each review.

Grant, M. J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies . Health Information & Libraries Journal, 26 , 91–108. doi:10.1111/j.1471-1842.2009.00848.x

What's the difference between reviews?

Researchers, academics, and librarians all use various terms to describe different types of literature reviews, and there is often inconsistency in the ways the types are discussed. Here are a couple of simple explanations.

• The image below describes common review types in terms of speed, detail, risk of bias, and comprehensiveness:

"Schematic of the main differences between the types of literature review" by Brennan, M. L., Arlt, S. P., Belshaw, Z., Buckley, L., Corah, L., Doit, H., Fajt, V. R., Grindlay, D., Moberly, H. K., Morrow, L. D., Stavisky, J., & White, C. (2020). Critically Appraised Topics (CATs) in veterinary medicine: Applying evidence in clinical practice. Frontiers in Veterinary Science, 7 , 314. https://doi.org/10.3389/fvets.2020.00314 is licensed under CC BY 3.0

• The table below lists four of the most common types of review , as adapted from a widely used typology of fourteen types of reviews (Grant & Booth, 2009).  

Grant, M.J. & Booth, A. (2009).  A typology of reviews: An analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26 (2), 91-108. https://doi.org/10.1111/j.1471-1842.2009.00848.x

See also the Library's  Literature Review guide.

Critical Appraised Topic (CAT)

For information on conducting a Critically Appraised Topic or CAT

Callander, J., Anstey, A. V., Ingram, J. R., Limpens, J., Flohr, C., & Spuls, P. I. (2017).  How to write a Critically Appraised Topic: evidence to underpin routine clinical practice.  British Journal of Dermatology (1951), 177(4), 1007-1013. https://doi.org/10.1111/bjd.15873 

Books on Literature Reviews

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Systematic Reviews: Types of literature review, methods, & resources

• Types of literature review, methods, & resources
• Protocol and registration
• Search strategy
• Medical Literature Databases to search
• Study selection and appraisal
• Data Extraction/Coding/Study characteristics/Results
• Reporting the quality/risk of bias
• Manage citations using RefWorks This link opens in a new window
• GW Box file storage for PDF's This link opens in a new window

Analytical reviews

GUIDELINES FOR HOW TO CARRY OUT AN ANALYTICAL REVIEW OF QUANTITATIVE RESEARCH

Enhancing the QUAlity and Transparency Of health Research (EQUATOR) network. (Tracking and listing over 550 reporting guidelines for various different study types including Randomised trials, Systematic reviews, Study protocols, Diagnostic/prognostic studies, Case reports, Clinical practice guidelines, Animal pre-clinical studies, etc). http://www.equator-network.org/resource-centre/library-of-health-research-reporting/

When comparing therapies :

PRISMA (Guideline on how to perform and write-up a systematic review and/or meta-analysis of the outcomes reported in multiple clinical trials of therapeutic interventions. PRISMA  replaces the previous QUORUM statement guidelines ):  Liberati, A,, Altman, D,, Moher, D, et al. (2009). The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.  Plos Medicine, 6 (7):e1000100. doi:10.1371/journal.pmed.1000100 

When comparing diagnostic methods :

Checklist for Artificial Intelligence in Medical Imaging (CLAIM). CLAIM is modeled after the STARD guideline and has been extended to address applications of AI in medical imaging that include classification, image reconstruction, text analysis, and workflow optimization. The elements described here should be viewed as a “best practice” to guide authors in presenting their research. Reported in Mongan, J., Moy, L., & Kahn, C. E., Jr (2020). Checklist for Artificial Intelligence in Medical Imaging (CLAIM): A Guide for Authors and Reviewers.  Radiology. Artificial intelligence ,  2 (2), e200029. https://doi.org/10.1148/ryai.2020200029

STAndards for the Reporting of Diagnostic accuracy studies (STARD) Statement. (Reporting guidelines for writing up a study comparing the accuracy of competing diagnostic methods)  http://www.stard-statement.org/

When evaluating clinical practice guidelines :

AGREE Research Trust (ART) (2013).  Appraisal of Guidelines for Research & Evaluation (AGREE-II) . (A 23-item instrument for as sessing th e quality of Clinical Practice Guidelines. Used internationally for evaluating or deciding which guidelines could be recommended for use in practice or to inform health policy decisions.)

National Guideline Clearinghouse Extent of Adherence to Trustworthy Standards (NEATS) Instrument (2019). (A 15-item instrument using scales of 1-5 to evaluate a guideline's adherence to the Institute of Medicine's standard for trustworthy guidelines. It has good external validity among guideline developers and good interrater reliability across trained reviewers.)

When reviewing genetics studies

Human genetics review reporting guidelines.  Little J, Higgins JPT (eds.). The HuGENet™ HuGE Review Handbook, version 1.0 . 

When you need to re-analyze individual participant data

If you wish to collect, check, and re-analyze individual participant data (IPD) from clinical trials addressing a particular research question, you should follow the  PRISMA-IPD  guidelines as reported in  Stewart, L.A., Clarke, M., Rovers, M., et al. (2015). Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data: The PRISMA-IPD Statement. JAMA, 313(16):1657-1665. doi:10.1001/jama.2015.3656 .

When comparing Randomized studies involving animals, livestock, or food:

O’Connor AM, et al. (2010).  The REFLECT statement: methods and processes of creating reporting guidelines for randomized controlled trials for livestock and food safety by modifying the CONSORT statement.  Zoonoses Public Health. 57(2):95-104. Epub 2010/01/15. doi: 10.1111/j.1863-2378.2009.01311.x. PubMed PMID: 20070653.

Sargeant JM, et al. (2010).  The REFLECT Statement: Reporting Guidelines for Randomized Controlled Trials in Livestock and Food Safety: Explanation and Elaboration.  Zoonoses Public Health. 57(2):105-36. Epub 2010/01/15. doi: JVB1312 [pii] 10.1111/j.1863-2378.2009.01312.x. PubMed PMID: 20070652.

GUIDELINES FOR HOW TO WRITE UP FOR PUBLICATION THE RESULTS OF ONE QUANTITATIVE CLINICAL TRIAL

When reporting the results of a Randomized Controlled Trial :

Consolidated Standards of Reporting Trials (CONSORT) Statement. (2010 reporting guideline for writing up a Randomized Controlled Clinical Trial).  http://www.consort-statement.org . Since updated in 2022, see Butcher, M. A., et al. (2022). Guidelines for Reporting Outcomes in Trial Reports: The CONSORT-Outcomes 2022 Extension . JAMA : the Journal of the American Medical Association, 328(22), 2252–2264. https://doi.org/10.1001/jama.2022.21022

Kilkenny, C., Browne, W. J., Cuthill, I. C., Emerson, M., & Altman, D. G. (2010). Improving bioscience research reporting: The ARRIVE guidelines for reporting animal research. PLoS Biology, 8(6), e1000412–e1000412. https://doi.org/10.1371/journal.pbio.1000412 (A 20-item checklist, following the CONSORT approach, listing the information that published articles reporting research using animals should include, such as the number and specific characteristics of animals used; details of housing and husbandry; and the experimental, statistical, and analytical methods used to reduce bias.)

Narrative reviews

GUIDELINES  FOR HOW TO CARRY OUT  A  NARRATIVE REVIEW / QUALITATIVE RESEARCH /  OBSERVATIONAL STUDIES

Campbell, M. (2020). Synthesis without meta-analysis (SWiM) in systematic reviews: reporting guideline. BMJ, 368. doi: https://doi.org/10.1136/bmj.l6890  (guideline on how to analyse evidence for a narrative review, to provide a recommendation based on heterogenous study types).

Community Preventive Services Task Force (2021).  The Methods Manual for Community Guide Systematic Reviews . (Public Health Prevention systematic review guidelines)

Enhancing the QUAlity and Transparency Of health Research (EQUATOR) network. (Tracking and listing over 550 reporting guidelines for various different study types including Observational studies, Qualitative research, Quality improvement studies, and Economic evaluations). http://www.equator-network.org/resource-centre/library-of-health-research-reporting/

Cochrane Qualitative & Implementation Methods Group. (2019). Training resources. Retrieved from  https://methods.cochrane.org/qi/training-resources . (Training materials for how to do a meta-synthesis, or qualitative evidence synthesis). 

Cornell University Library (2019). Planning worksheet for structured literature reviews. Retrieved 4/8/22 from  https://osf.io/tnfm7/  (offers a framework for a narrative literature review).

Green, B. N., Johnson, C. D., & Adams, A. (2006).  Writing narrative literature reviews for peer-reviewed journals: secrets of the trade . Journal of Chiropractic Medicine, 5(3): 101-117. DOI: 10.1016/ S0899-3467 (07)60142-6.  This is a very good article about what to take into consideration when writing any type of narrative review.

When reviewing observational studies/qualitative research :

STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement. (Reporting guidelines for various types of health sciences observational studies).  http://www.strobe-statement.org 

Meta-analysis of Observational Studies in Epidemiology (MOOSE)  http://jama.jamanetwork.com/article.aspx?articleid=192614

RATS Qualitative research systematic review guidelines.  https://www.equator-network.org/reporting-guidelines/qualitative-research-review-guidelines-rats/

Methods/Guidance

Right Review , this decision support website provides an algorithm to help reviewers choose a review methodology from among 41 knowledge synthesis methods.

The Systematic Review Toolbox , an online catalogue of tools that support various tasks within the systematic review and wider evidence synthesis process. Maintained by the UK University of York Health Economics Consortium, Newcastle University NIHR Innovation Observatory, and University of Sheffield School of Health and Related Research.

Institute of Medicine. (2011).  Finding What Works in Health Care: Standards for Systematic Reviews . Washington, DC: National Academies  (Systematic review guidelines from the Health and Medicine Division (HMD) of the U.S. National Academies of Sciences, Engineering, and Medicine (formerly called the Institute of Medicine)).

International Committee of Medical Journal Editors (2022).  Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly work in Medical Journals . Guidance on how to prepare a manuscript for submission to a Medical journal.

Cochrane Handbook of Systematic Reviews of Interventions (International Cochrane Collaboration systematic review guidelines). The various Cochrane review groups comporise around 30,000 physicians around the world working in the disciplines on reviews of interventions with very detailed methods for verifying the validity of the research methods and analysis performed in screened-in Randmized Controlled Clinical Trials. Typically published Cochrane Reviews are the most exhaustive review of the evidence of effectiveness of a particular drug or intervention, and include a statistical meta-analysis. Similar to practice guidelines, Cochrane reviews are periodically revised and updated.

Joanna Briggs Institute (JBI) Manual of Evidence Synthesis . (International systematic review guidelines). Based at the University of Adelaide, South Australia, and collaborating with around 80 academic and medical entities around the world. Unlike Cochrane Reviews that strictly focus on efficacy of interventions, JBI offers a broader, inclusive approach to evidence, to accommodate a range of diverse questions and study designs. The JBI manual provides guidance on how to analyse and include both quantitative and qualitative research.

Cochrane Methods Support Unit, webinar recordings on methodological support questions 

Cochrane Qualitative & Implementation Methods Group. (2019). Training resources. Retrieved from https://methods.cochrane.org/qi/training-resources . (How to do a meta-synthesis, or qualitative evidence synthesis). 

Center for Reviews and Dissemination (University of York, England) (2009).  Systematic Reviews: CRD's guidance for undertaking systematic reviews in health care . (British systematic review guidelines). 

Agency for Health Research & Quality (AHRQ) (2013). Methods guide for effectiveness and comparative effectiveness reviews . (U.S. comparative effectiveness review guidelines)

Hunter, K. E., et al. (2022). Searching clinical trials registers: guide for systematic reviewers.  BMJ (Clinical research ed.) ,  377 , e068791. https://doi.org/10.1136/bmj-2021-068791

Patient-Centered Outcomes Research Institute (PCORI).  The PCORI Methodology Report . (A 47-item methodology checklist for U.S. patient-centered outcomes research. Established under the Patient Protection and Affordable Care Act, PCORI funds the development of guidance on the comparative effectivess of clinical healthcare, similar to the UK National Institute for Clinical Evidence but without reporting cost-effectiveness QALY metrics). 

Canadian Agency for Drugs and Technologies in Health (CADTH) (2019). Grey Matters: a practical tool for searching health-related grey literature. Retrieved from https://www.cadth.ca/resources/finding-evidence/grey-matters . A checklist of N American & international online databases and websites you can use to search for unpublished reports, posters, and policy briefs, on topics including general medicine and nursing, public and mental health, health technology assessment, drug and device regulatory, approvals, warnings, and advisories.

Hempel, S., Xenakis, L., & Danz, M. (2016). Systematic Reviews for Occupational Safety and Health Questions: Resources for Evidence Synthesis. Retrieved 8/15/16 from http://www.rand.org/pubs/research_reports/RR1463.html . NIOSH guidelines for how to carry out a systematic review in the occupational safety and health domain.

A good source for reporting guidelines is the  NLM's  Research Reporting Guidelines and Initiatives .

Grading of Recommendations Assessment, Development and Evaluation (GRADE). (An international group of academics/clinicians working to promote a common approach to grading the quality of evidence and strength of recommendations.) 

Phillips, B., Ball, C., Sackett, D., et al. (2009). Oxford Centre for Evidence Based Medicine: Levels of Evidence. Retrieved 3/20/17 from https://www.cebm.net/wp-content/uploads/2014/06/CEBM-Levels-of-Evidence-2.1.pdf . (Another commonly used criteria for grading the quality of evidence and strength of recommendations, developed in part by EBM guru David Sackett.) 

Systematic Reviews for Animals & Food  (guidelines including the REFLECT statement for carrying out a systematic review on animal health, animal welfare, food safety, livestock, and agriculture)

Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies . Health Information & Libraries Journal, 26(2), 91-108. doi:10.1111/j.1471-1842.2009.00848.x. (Describes 14 different types of literature and systematic review, useful for thinking at the outset about what sort of literature review you want to do.)

Sutton, A., Clowes, M., Preston, L., & Booth, A. (2019). Meeting the review family: exploring review types and associated information retrieval requirements . Health information and libraries journal, 36(3), 202–222. doi:10.1111/hir.12276  (An updated look at different types of literature review, expands on the Grant & Booth 2009 article listed above).

Garrard, J. (2007).  Health Sciences Literature Review Made Easy: The Matrix Method  (2nd Ed.).   Sudbury, MA:  Jones & Bartlett Publishers. (Textbook of health sciences literature search methods).

Zilberberg, M. (2012).  Between the lines: Finding the truth in medical literature . Goshen, MA: Evimed Research Press. (Concise book on foundational concepts of evidence-based medicine).

Lang, T. (2009). The Value of Systematic Reviews as Research Activities in Medical Education . In: Lang, T. How to write, publish, & present in the health sciences : a guide for clinicians & laboratory researchers. Philadelphia : American College of Physicians.  (This book chapter has a helpful bibliography on systematic review and meta-analysis methods)

Brown, S., Martin, E., Garcia, T., Winter, M., García, A., Brown, A., Cuevas H.,  & Sumlin, L. (2013). Managing complex research datasets using electronic tools: a meta-analysis exemplar . Computers, Informatics, Nursing: CIN, 31(6), 257-265. doi:10.1097/NXN.0b013e318295e69c. (This article advocates for the programming of electronic fillable forms in Adobe Acrobat Pro to feed data into Excel or SPSS for analysis, and to use cloud based file sharing systems such as Blackboard, RefWorks, or EverNote to facilitate sharing knowledge about the decision-making process and keep data secure. Of particular note are the flowchart describing this process, and their example screening form used for the initial screening of abstracts).

Brown, S., Upchurch, S., & Acton, G. (2003). A framework for developing a coding scheme for meta-analysis . Western Journal Of Nursing Research, 25(2), 205-222. (This article describes the process of how to design a coded data extraction form and codebook, Table 1 is an example of a coded data extraction form that can then be used to program a fillable form in Adobe Acrobat or Microsoft Access).

Elamin, M. B., Flynn, D. N., Bassler, D., Briel, M., Alonso-Coello, P., Karanicolas, P., & ... Montori, V. M. (2009). Choice of data extraction tools for systematic reviews depends on resources and review complexity .  Journal Of Clinical Epidemiology ,  62 (5), 506-510. doi:10.1016/j.jclinepi.2008.10.016  (This article offers advice on how to decide what tools to use to extract data for analytical systematic reviews).

Riegelman R.   Studying a Study and Testing a Test: Reading Evidence-based Health Research , 6th Edition.  Lippincott Williams & Wilkins, 2012. (Textbook of quantitative statistical methods used in health sciences research).

Rathbone, J., Hoffmann, T., & Glasziou, P. (2015). Faster title and abstract screening? Evaluating Abstrackr, a semi-automated online screening program for systematic reviewers. Systematic Reviews, 480. doi:10.1186/s13643-015-0067-6

Guyatt, G., Rennie, D., Meade, M., & Cook, D. (2015). Users' guides to the medical literature (3rd ed.). New York: McGraw-Hill Education Medical.  (This is a foundational textbook on evidence-based medicine and of particular use to the reviewer who wants to learn about the different types of published research article e.g. "what is a case report?" and to understand what types of study design best answer what types of clinical question).

Glanville, J., Duffy, S., Mccool, R., & Varley, D. (2014). Searching ClinicalTrials.gov and the International Clinical Trials Registry Platform to inform systematic reviews: what are the optimal search approaches? Journal of the Medical Library Association : JMLA, 102(3), 177–183. https://doi.org/10.3163/1536-5050.102.3.007

Ouzzani, M., Hammady, H., Fedorowicz, Z., & Elmagarmid, A. (2016). Rayyan a web and mobile app for systematic reviews.  Systematic Reviews, 5 : 210, DOI: 10.1186/s13643-016-0384-4. http://rdcu.be/nzDM

Kwon Y, Lemieux M, McTavish J, Wathen N. (2015). Identifying and removing duplicate records from systematic review searches. J Med Libr Assoc. 103 (4): 184-8. doi: 10.3163/1536-5050.103.4.004. https://www.ncbi.nlm.nih.gov/pubmed/26512216

Bramer WM, Giustini D, de Jonge GB, Holland L, Bekhuis T. (2016). De-duplication of database search results for systematic reviews in EndNote. J Med Libr Assoc. 104 (3):240-3. doi: 10.3163/1536-5050.104.3.014. Erratum in: J Med Libr Assoc. 2017 Jan;105(1):111. https://www.ncbi.nlm.nih.gov/pubmed/27366130

McGowan J, Sampson M, Salzwedel DM, Cogo E, Foerster V, Lefebvre C. PRESS Peer Review of Electronic Search Strategies: 2015 Guideline Statement. J Clin Epidemiol. 2016;75:40–46. doi: 10.1016/j.jclinepi.2016.01.021 . PRESS is a guideline with a checklist for librarians to critically appraise the search strategy for a systematic review literature search.

Clark, JM, Sanders, S, Carter, M, Honeyman, D, Cleo, G, Auld, Y, Booth, D, Condron, P, Dalais, C, Bateup, S, Linthwaite, B, May, N, Munn, J, Ramsay, L, Rickett, K, Rutter, C, Smith, A, Sondergeld, P, Wallin, M, Jones, M & Beller, E 2020, 'Improving the translation of search strategies using the Polyglot Search Translator: a randomized controlled trial',  Journal of the Medical Library Association , vol. 108, no. 2, pp. 195-207.

Journal articles describing systematic review methods can be searched for in PubMed using this search string in the PubMed search box: sysrev_methods [sb] . 

Software tools for systematic reviews

• Covidence GW in 2019 has bought a subscription to this Cloud based tool for facilitating screening decisions, used by the Cochrane Collaboration. Register for an account.
• NVIVO for analysis of qualitative research NVIVO is used for coding interview data to identify common themes emerging from interviews with several participants. GW faculty, staff, and students may download NVIVO software.
• RedCAP RedCAP is software that can be used to create survey forms for research or data collection or data extraction. It has very detailed functionality to enable data exchange with Electronic Health Record Systems, and to integrate with study workflow such as scheduling follow up reminders for study participants.
• SRDR tool from AHRQ Free, web-based and has a training environment, tutorials, and example templates of systematic review data extraction forms
• RevMan 5 RevMan 5 is the desktop version of the software used by Cochrane systematic review teams. RevMan 5 is free for academic use and can be downloaded and configured to run as stand alone software that does not connect with the Cochrane server if you follow the instructions at https://training.cochrane.org/online-learning/core-software-cochrane-reviews/revman/revman-5-download/non-cochrane-reviews
• Rayyan Free, web-based tool for collecting and screening citations. It has options to screen with multiple people, masking each other.
• GradePro Free, web application to create, manage and share summaries of research evidence (called Evidence Profiles and Summary of Findings Tables) for reviews or guidelines, uses the GRADE criteria to evaluate each paper under review.
• DistillerSR Needs subscription. Create coded data extraction forms from templates.
• EPPI Reviewer Needs subscription. Like DistillerSR, tool for text mining, data clustering, classification and term extraction
• SUMARI Needs subscription. Qualitative data analysis.
• Dedoose Needs subscription. Qualitative data analysis, similar to NVIVO in that it can be used to code interview transcripts, identify word co-occurence, cloud based.
• Meta-analysis software for statistical analysis of data for quantitative reviews SPSS, SAS, and STATA are popular analytical statistical software that include macros for carrying out meta-analysis. Himmelfarb has SPSS on some 3rd floor computers, and GW affiliates may download SAS to your own laptop from the Division of IT website. To perform mathematical analysis of big data sets there are statistical analysis software libraries in the R programming language available through GitHub and RStudio, but this requires advanced knowledge of the R and Python computer languages and data wrangling/cleaning.
• PRISMA 2020 flow diagram generator The PRISMA Statement website has a page listing example flow diagram templates and a link to software for creating PRISMA 2020 flow diagrams using R software.

GW researchers may want to consider using Refworks to manage citations, and GW Box to store the full text PDF's of review articles. You can also use online survey forms such as Qualtrics, RedCAP, or Survey Monkey, to design and create your own coded fillable forms, and export the data to Excel or one of the qualitative analytical software tools listed above.

Forest Plot Generators

• RevMan 5 the desktop version of the software used by Cochrane systematic review teams. RevMan 5 is free for academic use and can be downloaded and configured to run as stand alone software that does not connect with the Cochrane server if you follow the instructions at https://training.cochrane.org/online-learning/core-software-cochrane-reviews/revman/revman-5-download/non-cochrane-reviews.
• Meta-Essentials a free set of workbooks designed for Microsoft Excel that, based on your input, automatically produce meta-analyses including Forest Plots. Produced for Erasmus University Rotterdam joint research institute.
• Neyeloff, Fuchs & Moreira Another set of Excel worksheets and instructions to generate a Forest Plot. Published as Neyeloff, J.L., Fuchs, S.C. & Moreira, L.B. Meta-analyses and Forest plots using a microsoft excel spreadsheet: step-by-step guide focusing on descriptive data analysis. BMC Res Notes 5, 52 (2012). https://doi-org.proxygw.wrlc.org/10.1186/1756-0500-5-52
• For R programmers instructions are at https://cran.r-project.org/web/packages/forestplot/vignettes/forestplot.html and you can download the R code package from https://github.com/gforge/forestplot
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• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
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• Last Updated: Sep 21, 2022 2:16 PM
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• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

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Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
• Critically evaluate: mention the strengths and weaknesses of your sources.
• Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

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Methodological Approaches to Literature Review

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• Dennis Thomas 2 ,
• Elida Zairina 3 &
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The literature review can serve various functions in the contexts of education and research. It aids in identifying knowledge gaps, informing research methodology, and developing a theoretical framework during the planning stages of a research study or project, as well as reporting of review findings in the context of the existing literature. This chapter discusses the methodological approaches to conducting a literature review and offers an overview of different types of reviews. There are various types of reviews, including narrative reviews, scoping reviews, and systematic reviews with reporting strategies such as meta-analysis and meta-synthesis. Review authors should consider the scope of the literature review when selecting a type and method. Being focused is essential for a successful review; however, this must be balanced against the relevance of the review to a broad audience.

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Akobeng AK. Principles of evidence based medicine. Arch Dis Child. 2005;90(8):837–40.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Alharbi A, Stevenson M. Refining Boolean queries to identify relevant studies for systematic review updates. J Am Med Inform Assoc. 2020;27(11):1658–66.

Article   PubMed   PubMed Central   Google Scholar  

Arksey H, O’Malley L. Scoping studies: towards a methodological framework. Int J Soc Res Methodol. 2005;8(1):19–32.

Article   Google Scholar  

Aromataris E MZE. JBI manual for evidence synthesis. 2020.

Google Scholar  

Aromataris E, Pearson A. The systematic review: an overview. Am J Nurs. 2014;114(3):53–8.

Article   PubMed   Google Scholar  

Aromataris E, Riitano D. Constructing a search strategy and searching for evidence. A guide to the literature search for a systematic review. Am J Nurs. 2014;114(5):49–56.

Babineau J. Product review: covidence (systematic review software). J Canad Health Libr Assoc Canada. 2014;35(2):68–71.

Baker JD. The purpose, process, and methods of writing a literature review. AORN J. 2016;103(3):265–9.

Bastian H, Glasziou P, Chalmers I. Seventy-five trials and eleven systematic reviews a day: how will we ever keep up? PLoS Med. 2010;7(9):e1000326.

Bramer WM, Rethlefsen ML, Kleijnen J, Franco OH. Optimal database combinations for literature searches in systematic reviews: a prospective exploratory study. Syst Rev. 2017;6(1):1–12.

Brown D. A review of the PubMed PICO tool: using evidence-based practice in health education. Health Promot Pract. 2020;21(4):496–8.

Cargo M, Harris J, Pantoja T, et al. Cochrane qualitative and implementation methods group guidance series – paper 4: methods for assessing evidence on intervention implementation. J Clin Epidemiol. 2018;97:59–69.

Cook DJ, Mulrow CD, Haynes RB. Systematic reviews: synthesis of best evidence for clinical decisions. Ann Intern Med. 1997;126(5):376–80.

Article   CAS   PubMed   Google Scholar  

Counsell C. Formulating questions and locating primary studies for inclusion in systematic reviews. Ann Intern Med. 1997;127(5):380–7.

Cummings SR, Browner WS, Hulley SB. Conceiving the research question and developing the study plan. In: Cummings SR, Browner WS, Hulley SB, editors. Designing Clinical Research: An Epidemiological Approach. 4th ed. Philadelphia (PA): P Lippincott Williams & Wilkins; 2007. p. 14–22.

Eriksen MB, Frandsen TF. The impact of patient, intervention, comparison, outcome (PICO) as a search strategy tool on literature search quality: a systematic review. JMLA. 2018;106(4):420.

Ferrari R. Writing narrative style literature reviews. Medical Writing. 2015;24(4):230–5.

Flemming K, Booth A, Hannes K, Cargo M, Noyes J. Cochrane qualitative and implementation methods group guidance series – paper 6: reporting guidelines for qualitative, implementation, and process evaluation evidence syntheses. J Clin Epidemiol. 2018;97:79–85.

Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Inf Libr J. 2009;26(2):91–108.

Green BN, Johnson CD, Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. J Chiropr Med. 2006;5(3):101–17.

Gregory AT, Denniss AR. An introduction to writing narrative and systematic reviews; tasks, tips and traps for aspiring authors. Heart Lung Circ. 2018;27(7):893–8.

Harden A, Thomas J, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 5: methods for integrating qualitative and implementation evidence within intervention effectiveness reviews. J Clin Epidemiol. 2018;97:70–8.

Harris JL, Booth A, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 2: methods for question formulation, searching, and protocol development for qualitative evidence synthesis. J Clin Epidemiol. 2018;97:39–48.

Higgins J, Thomas J. In: Chandler J, Cumpston M, Li T, Page MJ, Welch VA, editors. Cochrane Handbook for Systematic Reviews of Interventions version 6.3, updated February 2022). Available from www.training.cochrane.org/handbook.: Cochrane; 2022.

International prospective register of systematic reviews (PROSPERO). Available from https://www.crd.york.ac.uk/prospero/ .

Khan KS, Kunz R, Kleijnen J, Antes G. Five steps to conducting a systematic review. J R Soc Med. 2003;96(3):118–21.

Landhuis E. Scientific literature: information overload. Nature. 2016;535(7612):457–8.

Lockwood C, Porritt K, Munn Z, Rittenmeyer L, Salmond S, Bjerrum M, Loveday H, Carrier J, Stannard D. Chapter 2: Systematic reviews of qualitative evidence. In: Aromataris E, Munn Z, editors. JBI Manual for Evidence Synthesis. JBI; 2020. Available from https://synthesismanual.jbi.global . https://doi.org/10.46658/JBIMES-20-03 .

Chapter   Google Scholar  

Lorenzetti DL, Topfer L-A, Dennett L, Clement F. Value of databases other than medline for rapid health technology assessments. Int J Technol Assess Health Care. 2014;30(2):173–8.

Moher D, Liberati A, Tetzlaff J, Altman DG, the PRISMA Group. Preferred reporting items for (SR) and meta-analyses: the PRISMA statement. Ann Intern Med. 2009;6:264–9.

Mulrow CD. Systematic reviews: rationale for systematic reviews. BMJ. 1994;309(6954):597–9.

Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018;18(1):143.

Munthe-Kaas HM, Glenton C, Booth A, Noyes J, Lewin S. Systematic mapping of existing tools to appraise methodological strengths and limitations of qualitative research: first stage in the development of the CAMELOT tool. BMC Med Res Methodol. 2019;19(1):1–13.

Murphy CM. Writing an effective review article. J Med Toxicol. 2012;8(2):89–90.

NHMRC. Guidelines for guidelines: assessing risk of bias. Available at https://nhmrc.gov.au/guidelinesforguidelines/develop/assessing-risk-bias . Last published 29 August 2019. Accessed 29 Aug 2022.

Noyes J, Booth A, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 1: introduction. J Clin Epidemiol. 2018b;97:35–8.

Noyes J, Booth A, Flemming K, et al. Cochrane qualitative and implementation methods group guidance series – paper 3: methods for assessing methodological limitations, data extraction and synthesis, and confidence in synthesized qualitative findings. J Clin Epidemiol. 2018a;97:49–58.

Noyes J, Booth A, Moore G, Flemming K, Tunçalp Ö, Shakibazadeh E. Synthesising quantitative and qualitative evidence to inform guidelines on complex interventions: clarifying the purposes, designs and outlining some methods. BMJ Glob Health. 2019;4(Suppl 1):e000893.

Peters MD, Godfrey CM, Khalil H, McInerney P, Parker D, Soares CB. Guidance for conducting systematic scoping reviews. Int J Evid Healthcare. 2015;13(3):141–6.

Polanin JR, Pigott TD, Espelage DL, Grotpeter JK. Best practice guidelines for abstract screening large-evidence systematic reviews and meta-analyses. Res Synth Methods. 2019;10(3):330–42.

Article   PubMed Central   Google Scholar  

Shea BJ, Grimshaw JM, Wells GA, et al. Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews. BMC Med Res Methodol. 2007;7(1):1–7.

Shea BJ, Reeves BC, Wells G, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. Brit Med J. 2017;358

Sterne JA, Hernán MA, Reeves BC, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. Br Med J. 2016;355

Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA. 2000;283(15):2008–12.

Tawfik GM, Dila KAS, Mohamed MYF, et al. A step by step guide for conducting a systematic review and meta-analysis with simulation data. Trop Med Health. 2019;47(1):1–9.

The Critical Appraisal Program. Critical appraisal skills program. Available at https://casp-uk.net/ . 2022. Accessed 29 Aug 2022.

The University of Melbourne. Writing a literature review in Research Techniques 2022. Available at https://students.unimelb.edu.au/academic-skills/explore-our-resources/research-techniques/reviewing-the-literature . Accessed 29 Aug 2022.

The Writing Center University of Winconsin-Madison. Learn how to write a literature review in The Writer’s Handbook – Academic Professional Writing. 2022. Available at https://writing.wisc.edu/handbook/assignments/reviewofliterature/ . Accessed 29 Aug 2022.

Thompson SG, Sharp SJ. Explaining heterogeneity in meta-analysis: a comparison of methods. Stat Med. 1999;18(20):2693–708.

Tricco AC, Lillie E, Zarin W, et al. A scoping review on the conduct and reporting of scoping reviews. BMC Med Res Methodol. 2016;16(1):15.

Tricco AC, Lillie E, Zarin W, et al. PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Ann Intern Med. 2018;169(7):467–73.

Yoneoka D, Henmi M. Clinical heterogeneity in random-effect meta-analysis: between-study boundary estimate problem. Stat Med. 2019;38(21):4131–45.

Yuan Y, Hunt RH. Systematic reviews: the good, the bad, and the ugly. Am J Gastroenterol. 2009;104(5):1086–92.

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Thomas, D., Zairina, E., George, J. (2023). Methodological Approaches to Literature Review. In: Encyclopedia of Evidence in Pharmaceutical Public Health and Health Services Research in Pharmacy. Springer, Cham. https://doi.org/10.1007/978-3-030-50247-8_57-1

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Types of Literature Review

There are many types of literature review. The choice of a specific type depends on your research approach and design. The following types of literature review are the most popular in business studies:

Narrative literature review , also referred to as traditional literature review, critiques literature and summarizes the body of a literature. Narrative review also draws conclusions about the topic and identifies gaps or inconsistencies in a body of knowledge. You need to have a sufficiently focused research question to conduct a narrative literature review

Systematic literature review requires more rigorous and well-defined approach compared to most other types of literature review. Systematic literature review is comprehensive and details the timeframe within which the literature was selected. Systematic literature review can be divided into two categories: meta-analysis and meta-synthesis.

When you conduct meta-analysis you take findings from several studies on the same subject and analyze these using standardized statistical procedures. In meta-analysis patterns and relationships are detected and conclusions are drawn. Meta-analysis is associated with deductive research approach.

Meta-synthesis, on the other hand, is based on non-statistical techniques. This technique integrates, evaluates and interprets findings of multiple qualitative research studies. Meta-synthesis literature review is conducted usually when following inductive research approach.

Scoping literature review , as implied by its name is used to identify the scope or coverage of a body of literature on a given topic. It has been noted that “scoping reviews are useful for examining emerging evidence when it is still unclear what other, more specific questions can be posed and valuably addressed by a more precise systematic review.” [1] The main difference between systematic and scoping types of literature review is that, systematic literature review is conducted to find answer to more specific research questions, whereas scoping literature review is conducted to explore more general research question.

Argumentative literature review , as the name implies, examines literature selectively in order to support or refute an argument, deeply imbedded assumption, or philosophical problem already established in the literature. It should be noted that a potential for bias is a major shortcoming associated with argumentative literature review.

Integrative literature review reviews , critiques, and synthesizes secondary data about research topic in an integrated way such that new frameworks and perspectives on the topic are generated. If your research does not involve primary data collection and data analysis, then using integrative literature review will be your only option.

Theoretical literature review focuses on a pool of theory that has accumulated in regard to an issue, concept, theory, phenomena. Theoretical literature reviews play an instrumental role in establishing what theories already exist, the relationships between them, to what degree existing theories have been investigated, and to develop new hypotheses to be tested.

At the earlier parts of the literature review chapter, you need to specify the type of your literature review your chose and justify your choice. Your choice of a specific type of literature review should be based upon your research area, research problem and research methods.  Also, you can briefly discuss other most popular types of literature review mentioned above, to illustrate your awareness of them.

[1] Munn, A. et. al. (2018) “Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach” BMC Medical Research Methodology

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• Research Guides
• Evidence Synthesis, Systematic Review Services
• Literature Review Types, Taxonomies

Evidence Synthesis, Systematic Review Services : Literature Review Types, Taxonomies

• Develop a Protocol
• Develop Your Research Question
• Select Databases
• Select Gray Literature Sources
• Write a Search Strategy
• Manage Your Search Process
• Register Your Protocol
• Citation Management
• Article Screening
• Risk of Bias Assessment
• Synthesize, Map, or Describe the Results
• Find Guidance by Discipline
• Manage Your Research Data
• Browse Evidence Portals by Discipline
• Automate the Process, Tools & Technologies
• Additional Resources

Choosing a Literature Review Methodology

Growing interest in evidence-based practice has driven an increase in review methodologies. Your choice of review methodology (or literature review type) will be informed by the intent (purpose, function) of your research project and the time and resources of your team. 

• Decision Tree (What Type of Review is Right for You?) Developed by Cornell University Library staff, this "decision-tree" guides the user to a handful of review guides given time and intent.

Types of Evidence Synthesis*

Critical Review - Aims to demonstrate writer has extensively researched literature and critically evaluated its quality. Goes beyond mere description to include degree of analysis and conceptual innovation. Typically results in hypothesis or model.

Mapping Review (Systematic Map) - Map out and categorize existing literature from which to commission further reviews and/or primary research by identifying gaps in research literature.

Meta-Analysis - Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results.

Mixed Studies Review (Mixed Methods Review) - Refers to any combination of methods where one significant component is a literature review (usually systematic). Within a review context it refers to a combination of review approaches for example combining quantitative with qualitative research or outcome with process studies.

Narrative (Literature) Review - Generic term: published materials that provide examination of recent or current literature. Can cover wide range of subjects at various levels of completeness and comprehensiveness.

Overview - Generic term: summary of the [medical] literature that attempts to survey the literature and describe its characteristics.

Qualitative Systematic Review or Qualitative Evidence Synthesis - Method for integrating or comparing the findings from qualitative studies. It looks for ‘themes’ or ‘constructs’ that lie in or across individual qualitative studies.

Rapid Review - Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research.

Scoping Review or Evidence Map - Preliminary assessment of potential size and scope of available research literature. Aims to identify nature and extent of research.

State-of-the-art Review - Tend to address more current matters in contrast to other combined retrospective and current approaches. May offer new perspectives on issue or point out area for further research.

Systematic Review - Seeks to systematically search for, appraise and synthesis research evidence, often adhering to guidelines on the conduct of a review. (An emerging subset includes Living Reviews or Living Systematic Reviews - A [review or] systematic review which is continually updated, incorporating relevant new evidence as it becomes available.)

Systematic Search and Review - Combines strengths of critical review with a comprehensive search process. Typically addresses broad questions to produce ‘best evidence synthesis.’

Umbrella Review - Specifically refers to review compiling evidence from multiple reviews into one accessible and usable document. Focuses on broad condition or problem for which there are competing interventions and highlights reviews that address these interventions and their results.

*These definitions are in Grant & Booth's "A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies."

Literature Review Types/Typologies, Taxonomies

Grant, M. J., and A. Booth. "A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies."  Health Information and Libraries Journal  26.2 (2009): 91-108.  DOI: 10.1111/j.1471-1842.2009.00848.x  Link

Munn, Zachary, et al. “Systematic Review or Scoping Review? Guidance for Authors When Choosing between a Systematic or Scoping Review Approach.” BMC Medical Research Methodology , vol. 18, no. 1, Nov. 2018, p. 143. DOI: 10.1186/s12874-018-0611-x. Link

Sutton, A., et al. "Meeting the Review Family: Exploring Review Types and Associated Information Retrieval Requirements."  Health Information and Libraries Journal  36.3 (2019): 202-22.  DOI: 10.1111/hir.12276  Link

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

Literature Reviews

• Types of reviews
• Getting started

Types of reviews and examples

Choosing a review type.

• 1. Define your research question
• 2. Plan your search
• 3. Search the literature
• 4. Organize your results
• 5. Synthesize your findings
• 6. Write the review
• Artificial intelligence (AI) tools
• Thompson Writing Studio This link opens in a new window
• Need to write a systematic review? This link opens in a new window

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• Meta-analysis
• Systematized

Definition:

"A term used to describe a conventional overview of the literature, particularly when contrasted with a systematic review (Booth et al., 2012, p. 265).

Characteristics:

• Provides examination of recent or current literature on a wide range of subjects
• Varying levels of completeness / comprehensiveness, non-standardized methodology
• May or may not include comprehensive searching, quality assessment or critical appraisal

Mitchell, L. E., & Zajchowski, C. A. (2022). The history of air quality in Utah: A narrative review.  Sustainability ,  14 (15), 9653.  doi.org/10.3390/su14159653

Booth, A., Papaioannou, D., & Sutton, A. (2012). Systematic approaches to a successful literature review. London: SAGE Publications Ltd.

"An assessment of what is already known about a policy or practice issue...using systematic review methods to search and critically appraise existing research" (Grant & Booth, 2009, p. 100).

• Assessment of what is already known about an issue
• Similar to a systematic review but within a time-constrained setting
• Typically employs methodological shortcuts, increasing risk of introducing bias, includes basic level of quality assessment
• Best suited for issues needing quick decisions and solutions (i.e., policy recommendations)

Learn more about the method:

Khangura, S., Konnyu, K., Cushman, R., Grimshaw, J., & Moher, D. (2012). Evidence summaries: the evolution of a rapid review approach.  Systematic reviews, 1 (1), 1-9.  https://doi.org/10.1186/2046-4053-1-10

Virginia Commonwealth University Libraries. (2021). Rapid Review Protocol .

Quarmby, S., Santos, G., & Mathias, M. (2019). Air quality strategies and technologies: A rapid review of the international evidence.  Sustainability, 11 (10), 2757.  https://doi.org/10.3390/su11102757

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies.  Health Information & Libraries Journal , 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Developed and refined by the Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre), this review "map[s] out and categorize[s] existing literature on a particular topic, identifying gaps in research literature from which to commission further reviews and/or primary research" (Grant & Booth, 2009, p. 97).

Although mapping reviews are sometimes called scoping reviews, the key difference is that mapping reviews focus on a review question, rather than a topic

Mapping reviews are "best used where a clear target for a more focused evidence product has not yet been identified" (Booth, 2016, p. 14)

Mapping review searches are often quick and are intended to provide a broad overview

Mapping reviews can take different approaches in what types of literature is focused on in the search

Cooper I. D. (2016). What is a "mapping study?".  Journal of the Medical Library Association: JMLA ,  104 (1), 76–78. https://doi.org/10.3163/1536-5050.104.1.013

Miake-Lye, I. M., Hempel, S., Shanman, R., & Shekelle, P. G. (2016). What is an evidence map? A systematic review of published evidence maps and their definitions, methods, and products.  Systematic reviews, 5 (1), 1-21.  https://doi.org/10.1186/s13643-016-0204-x

Tainio, M., Andersen, Z. J., Nieuwenhuijsen, M. J., Hu, L., De Nazelle, A., An, R., ... & de Sá, T. H. (2021). Air pollution, physical activity and health: A mapping review of the evidence.  Environment international ,  147 , 105954.  https://doi.org/10.1016/j.envint.2020.105954

Booth, A. (2016). EVIDENT Guidance for Reviewing the Evidence: a compendium of methodological literature and websites . ResearchGate. https://doi.org/10.13140/RG.2.1.1562.9842 . 

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies.  Health Information & Libraries Journal , 26(2), 91-108.  https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

"A type of review that has as its primary objective the identification of the size and quality of research in a topic area in order to inform subsequent review" (Booth et al., 2012, p. 269).

• Main purpose is to map out and categorize existing literature, identify gaps in literature—great for informing policy-making
• Search comprehensiveness determined by time/scope constraints, could take longer than a systematic review
• No formal quality assessment or critical appraisal

Learn more about the methods :

Arksey, H., & O'Malley, L. (2005) Scoping studies: towards a methodological framework.  International Journal of Social Research Methodology ,  8 (1), 19-32.  https://doi.org/10.1080/1364557032000119616

Levac, D., Colquhoun, H., & O’Brien, K. K. (2010). Scoping studies: Advancing the methodology. Implementation Science: IS, 5, 69. https://doi.org/10.1186/1748-5908-5-69

Example : 

Rahman, A., Sarkar, A., Yadav, O. P., Achari, G., & Slobodnik, J. (2021). Potential human health risks due to environmental exposure to nano-and microplastics and knowledge gaps: A scoping review.  Science of the Total Environment, 757 , 143872.  https://doi.org/10.1016/j.scitotenv.2020.143872

A review that "[compiles] evidence from multiple...reviews into one accessible and usable document" (Grant & Booth, 2009, p. 103). While originally intended to be a compilation of Cochrane reviews, it now generally refers to any kind of evidence synthesis.

• Compiles evidence from multiple reviews into one document
• Often defines a broader question than is typical of a traditional systematic review

Choi, G. J., & Kang, H. (2022). The umbrella review: a useful strategy in the rain of evidence.  The Korean Journal of Pain ,  35 (2), 127–128.  https://doi.org/10.3344/kjp.2022.35.2.127

Aromataris, E., Fernandez, R., Godfrey, C. M., Holly, C., Khalil, H., & Tungpunkom, P. (2015). Summarizing systematic reviews: Methodological development, conduct and reporting of an umbrella review approach. International Journal of Evidence-Based Healthcare , 13(3), 132–140. https://doi.org/10.1097/XEB.0000000000000055

Rojas-Rueda, D., Morales-Zamora, E., Alsufyani, W. A., Herbst, C. H., Al Balawi, S. M., Alsukait, R., & Alomran, M. (2021). Environmental risk factors and health: An umbrella review of meta-analyses.  International Journal of Environmental Research and Public Dealth ,  18 (2), 704.  https://doi.org/10.3390/ijerph18020704

A meta-analysis is a "technique that statistically combines the results of quantitative studies to provide a more precise effect of the result" (Grant & Booth, 2009, p. 98).

• Statistical technique for combining results of quantitative studies to provide more precise effect of results
• Aims for exhaustive, comprehensive searching
• Quality assessment may determine inclusion/exclusion criteria
• May be conducted independently or as part of a systematic review

Berman, N. G., & Parker, R. A. (2002). Meta-analysis: Neither quick nor easy. BMC Medical Research Methodology , 2(1), 10. https://doi.org/10.1186/1471-2288-2-10

Hites R. A. (2004). Polybrominated diphenyl ethers in the environment and in people: a meta-analysis of concentrations.  Environmental Science & Technology ,  38 (4), 945–956.  https://doi.org/10.1021/es035082g

A systematic review "seeks to systematically search for, appraise, and [synthesize] research evidence, often adhering to the guidelines on the conduct of a review" provided by discipline-specific organizations, such as the Cochrane Collaboration (Grant & Booth, 2009, p. 102).

• Aims to compile and synthesize all known knowledge on a given topic
• Adheres to strict guidelines, protocols, and frameworks
• Time-intensive and often takes months to a year or more to complete
• The most commonly referred to type of evidence synthesis. Sometimes confused as a blanket term for other types of reviews

Gascon, M., Triguero-Mas, M., Martínez, D., Dadvand, P., Forns, J., Plasència, A., & Nieuwenhuijsen, M. J. (2015). Mental health benefits of long-term exposure to residential green and blue spaces: a systematic review.  International Journal of Environmental Research and Public Health ,  12 (4), 4354–4379.  https://doi.org/10.3390/ijerph120404354

"Systematized reviews attempt to include one or more elements of the systematic review process while stopping short of claiming that the resultant output is a systematic review" (Grant & Booth, 2009, p. 102). When a systematic review approach is adapted to produce a more manageable scope, while still retaining the rigor of a systematic review such as risk of bias assessment and the use of a protocol, this is often referred to as a  structured review  (Huelin et al., 2015).

• Typically conducted by postgraduate or graduate students
• Often assigned by instructors to students who don't have the resources to conduct a full systematic review

Salvo, G., Lashewicz, B. M., Doyle-Baker, P. K., & McCormack, G. R. (2018). Neighbourhood built environment influences on physical activity among adults: A systematized review of qualitative evidence.  International Journal of Environmental Research and Public Health ,  15 (5), 897.  https://doi.org/10.3390/ijerph15050897

Huelin, R., Iheanacho, I., Payne, K., & Sandman, K. (2015). What’s in a name? Systematic and non-systematic literature reviews, and why the distinction matters. https://www.evidera.com/resource/whats-in-a-name-systematic-and-non-systematic-literature-reviews-and-why-the-distinction-matters/

• Review Decision Tree - Cornell University For more information, check out Cornell's review methodology decision tree.
• LitR-Ex.com - Eight literature review methodologies Learn more about 8 different review types (incl. Systematic Reviews and Scoping Reviews) with practical tips about strengths and weaknesses of different methods.
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• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
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Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health ( m-health ) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

• Ammenwerth E., de Keizer N. An inventory of evaluation studies of information technology in health care. Trends in evaluation research, 1982-2002. International Journal of Medical Informatics. 2004; 44 (1):44–56. [ PubMed : 15778794 ]
• Anderson S., Allen P., Peckham S., Goodwin N. Asking the right questions: scoping studies in the commissioning of research on the organisation and delivery of health services. Health Research Policy and Systems. 2008; 6 (7):1–12. [ PMC free article : PMC2500008 ] [ PubMed : 18613961 ] [ CrossRef ]
• Archer N., Fevrier-Thomas U., Lokker C., McKibbon K. A., Straus S.E. Personal health records: a scoping review. Journal of American Medical Informatics Association. 2011; 18 (4):515–522. [ PMC free article : PMC3128401 ] [ PubMed : 21672914 ]
• Arksey H., O’Malley L. Scoping studies: towards a methodological framework. International Journal of Social Research Methodology. 2005; 8 (1):19–32.
• A systematic, tool-supported method for conducting literature reviews in information systems. Paper presented at the Proceedings of the 19th European Conference on Information Systems ( ecis 2011); June 9 to 11; Helsinki, Finland. 2011.
• Baumeister R. F., Leary M.R. Writing narrative literature reviews. Review of General Psychology. 1997; 1 (3):311–320.
• Becker L. A., Oxman A.D. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Overviews of reviews; pp. 607–631.
• Borenstein M., Hedges L., Higgins J., Rothstein H. Introduction to meta-analysis. Hoboken, nj : John Wiley & Sons Inc; 2009.
• Cook D. J., Mulrow C. D., Haynes B. Systematic reviews: Synthesis of best evidence for clinical decisions. Annals of Internal Medicine. 1997; 126 (5):376–380. [ PubMed : 9054282 ]
• Cooper H., Hedges L.V. In: The handbook of research synthesis and meta-analysis. 2nd ed. Cooper H., Hedges L. V., Valentine J. C., editors. New York: Russell Sage Foundation; 2009. Research synthesis as a scientific process; pp. 3–17.
• Cooper H. M. Organizing knowledge syntheses: A taxonomy of literature reviews. Knowledge in Society. 1988; 1 (1):104–126.
• Cronin P., Ryan F., Coughlan M. Undertaking a literature review: a step-by-step approach. British Journal of Nursing. 2008; 17 (1):38–43. [ PubMed : 18399395 ]
• Darlow S., Wen K.Y. Development testing of mobile health interventions for cancer patient self-management: A review. Health Informatics Journal. 2015 (online before print). [ PubMed : 25916831 ] [ CrossRef ]
• Daudt H. M., van Mossel C., Scott S.J. Enhancing the scoping study methodology: a large, inter-professional team’s experience with Arksey and O’Malley’s framework. bmc Medical Research Methodology. 2013; 13 :48. [ PMC free article : PMC3614526 ] [ PubMed : 23522333 ] [ CrossRef ]
• Davies P. The relevance of systematic reviews to educational policy and practice. Oxford Review of Education. 2000; 26 (3-4):365–378.
• Deeks J. J., Higgins J. P. T., Altman D.G. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Analysing data and undertaking meta-analyses; pp. 243–296.
• Deshazo J. P., Lavallie D. L., Wolf F.M. Publication trends in the medical informatics literature: 20 years of “Medical Informatics” in mesh . bmc Medical Informatics and Decision Making. 2009; 9 :7. [ PMC free article : PMC2652453 ] [ PubMed : 19159472 ] [ CrossRef ]
• Dixon-Woods M., Agarwal S., Jones D., Young B., Sutton A. Synthesising qualitative and quantitative evidence: a review of possible methods. Journal of Health Services Research and Policy. 2005; 10 (1):45–53. [ PubMed : 15667704 ]
• Finfgeld-Connett D., Johnson E.D. Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews. Journal of Advanced Nursing. 2013; 69 (1):194–204. [ PMC free article : PMC3424349 ] [ PubMed : 22591030 ]
• Grady B., Myers K. M., Nelson E. L., Belz N., Bennett L., Carnahan L. … Guidelines Working Group. Evidence-based practice for telemental health. Telemedicine Journal and E Health. 2011; 17 (2):131–148. [ PubMed : 21385026 ]
• Green B. N., Johnson C. D., Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. Journal of Chiropractic Medicine. 2006; 5 (3):101–117. [ PMC free article : PMC2647067 ] [ PubMed : 19674681 ]
• Greenhalgh T., Wong G., Westhorp G., Pawson R. Protocol–realist and meta-narrative evidence synthesis: evolving standards ( rameses ). bmc Medical Research Methodology. 2011; 11 :115. [ PMC free article : PMC3173389 ] [ PubMed : 21843376 ]
• Gurol-Urganci I., de Jongh T., Vodopivec-Jamsek V., Atun R., Car J. Mobile phone messaging reminders for attendance at healthcare appointments. Cochrane Database System Review. 2013; 12 cd 007458. [ PMC free article : PMC6485985 ] [ PubMed : 24310741 ] [ CrossRef ]
• Hart C. Doing a literature review: Releasing the social science research imagination. London: SAGE Publications; 1998.
• Higgins J. P. T., Green S., editors. Cochrane handbook for systematic reviews of interventions: Cochrane book series. Hoboken, nj : Wiley-Blackwell; 2008.
• Jesson J., Matheson L., Lacey F.M. Doing your literature review: traditional and systematic techniques. Los Angeles & London: SAGE Publications; 2011.
• King W. R., He J. Understanding the role and methods of meta-analysis in IS research. Communications of the Association for Information Systems. 2005; 16 :1.
• Kirkevold M. Integrative nursing research — an important strategy to further the development of nursing science and nursing practice. Journal of Advanced Nursing. 1997; 25 (5):977–984. [ PubMed : 9147203 ]
• Kitchenham B., Charters S. ebse Technical Report Version 2.3. Keele & Durham. uk : Keele University & University of Durham; 2007. Guidelines for performing systematic literature reviews in software engineering.
• Kitsiou S., Paré G., Jaana M. Systematic reviews and meta-analyses of home telemonitoring interventions for patients with chronic diseases: a critical assessment of their methodological quality. Journal of Medical Internet Research. 2013; 15 (7):e150. [ PMC free article : PMC3785977 ] [ PubMed : 23880072 ]
• Kitsiou S., Paré G., Jaana M. Effects of home telemonitoring interventions on patients with chronic heart failure: an overview of systematic reviews. Journal of Medical Internet Research. 2015; 17 (3):e63. [ PMC free article : PMC4376138 ] [ PubMed : 25768664 ]
• Levac D., Colquhoun H., O’Brien K. K. Scoping studies: advancing the methodology. Implementation Science. 2010; 5 (1):69. [ PMC free article : PMC2954944 ] [ PubMed : 20854677 ]
• Levy Y., Ellis T.J. A systems approach to conduct an effective literature review in support of information systems research. Informing Science. 2006; 9 :181–211.
• Liberati A., Altman D. G., Tetzlaff J., Mulrow C., Gøtzsche P. C., Ioannidis J. P. A. et al. Moher D. The prisma statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. Annals of Internal Medicine. 2009; 151 (4):W-65. [ PubMed : 19622512 ]
• Lyden J. R., Zickmund S. L., Bhargava T. D., Bryce C. L., Conroy M. B., Fischer G. S. et al. McTigue K. M. Implementing health information technology in a patient-centered manner: Patient experiences with an online evidence-based lifestyle intervention. Journal for Healthcare Quality. 2013; 35 (5):47–57. [ PubMed : 24004039 ]
• Mickan S., Atherton H., Roberts N. W., Heneghan C., Tilson J.K. Use of handheld computers in clinical practice: a systematic review. bmc Medical Informatics and Decision Making. 2014; 14 :56. [ PMC free article : PMC4099138 ] [ PubMed : 24998515 ]
• Moher D. The problem of duplicate systematic reviews. British Medical Journal. 2013; 347 (5040) [ PubMed : 23945367 ] [ CrossRef ]
• Montori V. M., Wilczynski N. L., Morgan D., Haynes R. B., Hedges T. Systematic reviews: a cross-sectional study of location and citation counts. bmc Medicine. 2003; 1 :2. [ PMC free article : PMC281591 ] [ PubMed : 14633274 ]
• Mulrow C. D. The medical review article: state of the science. Annals of Internal Medicine. 1987; 106 (3):485–488. [ PubMed : 3813259 ] [ CrossRef ]
• Evidence-based information systems: A decade later. Proceedings of the European Conference on Information Systems ; 2011. Retrieved from http://aisel ​.aisnet.org/cgi/viewcontent ​.cgi?article ​=1221&context ​=ecis2011 .
• Okoli C., Schabram K. A guide to conducting a systematic literature review of information systems research. ssrn Electronic Journal. 2010
• Otte-Trojel T., de Bont A., Rundall T. G., van de Klundert J. How outcomes are achieved through patient portals: a realist review. Journal of American Medical Informatics Association. 2014; 21 (4):751–757. [ PMC free article : PMC4078283 ] [ PubMed : 24503882 ]
• Paré G., Trudel M.-C., Jaana M., Kitsiou S. Synthesizing information systems knowledge: A typology of literature reviews. Information & Management. 2015; 52 (2):183–199.
• Patsopoulos N. A., Analatos A. A., Ioannidis J.P. A. Relative citation impact of various study designs in the health sciences. Journal of the American Medical Association. 2005; 293 (19):2362–2366. [ PubMed : 15900006 ]
• Paul M. M., Greene C. M., Newton-Dame R., Thorpe L. E., Perlman S. E., McVeigh K. H., Gourevitch M.N. The state of population health surveillance using electronic health records: A narrative review. Population Health Management. 2015; 18 (3):209–216. [ PubMed : 25608033 ]
• Pawson R. Evidence-based policy: a realist perspective. London: SAGE Publications; 2006.
• Pawson R., Greenhalgh T., Harvey G., Walshe K. Realist review—a new method of systematic review designed for complex policy interventions. Journal of Health Services Research & Policy. 2005; 10 (Suppl 1):21–34. [ PubMed : 16053581 ]
• Petersen K., Vakkalanka S., Kuzniarz L. Guidelines for conducting systematic mapping studies in software engineering: An update. Information and Software Technology. 2015; 64 :1–18.
• Petticrew M., Roberts H. Systematic reviews in the social sciences: A practical guide. Malden, ma : Blackwell Publishing Co; 2006.
• Rousseau D. M., Manning J., Denyer D. Evidence in management and organizational science: Assembling the field’s full weight of scientific knowledge through syntheses. The Academy of Management Annals. 2008; 2 (1):475–515.
• Rowe F. What literature review is not: diversity, boundaries and recommendations. European Journal of Information Systems. 2014; 23 (3):241–255.
• Shea B. J., Hamel C., Wells G. A., Bouter L. M., Kristjansson E., Grimshaw J. et al. Boers M. amstar is a reliable and valid measurement tool to assess the methodological quality of systematic reviews. Journal of Clinical Epidemiology. 2009; 62 (10):1013–1020. [ PubMed : 19230606 ]
• Shepperd S., Lewin S., Straus S., Clarke M., Eccles M. P., Fitzpatrick R. et al. Sheikh A. Can we systematically review studies that evaluate complex interventions? PLoS Medicine. 2009; 6 (8):e1000086. [ PMC free article : PMC2717209 ] [ PubMed : 19668360 ]
• Silva B. M., Rodrigues J. J., de la Torre Díez I., López-Coronado M., Saleem K. Mobile-health: A review of current state in 2015. Journal of Biomedical Informatics. 2015; 56 :265–272. [ PubMed : 26071682 ]
• Smith V., Devane D., Begley C., Clarke M. Methodology in conducting a systematic review of systematic reviews of healthcare interventions. bmc Medical Research Methodology. 2011; 11 (1):15. [ PMC free article : PMC3039637 ] [ PubMed : 21291558 ]
• Sylvester A., Tate M., Johnstone D. Beyond synthesis: re-presenting heterogeneous research literature. Behaviour & Information Technology. 2013; 32 (12):1199–1215.
• Templier M., Paré G. A framework for guiding and evaluating literature reviews. Communications of the Association for Information Systems. 2015; 37 (6):112–137.
• Thomas J., Harden A. Methods for the thematic synthesis of qualitative research in systematic reviews. bmc Medical Research Methodology. 2008; 8 (1):45. [ PMC free article : PMC2478656 ] [ PubMed : 18616818 ]
• Reconstructing the giant: on the importance of rigour in documenting the literature search process. Paper presented at the Proceedings of the 17th European Conference on Information Systems ( ecis 2009); Verona, Italy. 2009.
• Webster J., Watson R.T. Analyzing the past to prepare for the future: Writing a literature review. Management Information Systems Quarterly. 2002; 26 (2):11.
• Whitlock E. P., Lin J. S., Chou R., Shekelle P., Robinson K.A. Using existing systematic reviews in complex systematic reviews. Annals of Internal Medicine. 2008; 148 (10):776–782. [ PubMed : 18490690 ]

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• Cite this Page Paré G, Kitsiou S. Chapter 9 Methods for Literature Reviews. In: Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.
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Literature Review: Types of Literature Reviews

• Literature Review
• Purpose of a Literature Review
• Work in Progress
• Compiling & Writing
• Books, Articles, & Web Pages

Types of Literature Reviews

• Departmental Differences
• Citation Styles & Plagiarism
• Know the Difference! Systematic Review vs. Literature Review

It is important to think of knowledge in a given field as consisting of three layers.

• First, there are the primary studies that researchers conduct and publish.
• Second, are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the original studies.
• Third, there are the perceptions, conclusions, opinions, and interpretations that are shared informally that become part of the lore of the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews.

Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are several approaches to how they can be done, depending upon the type of analysis underpinning your study. Listed below are definitions of types of literature reviews:

Argumentative Review      This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews.

Integrative Review      Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication.

Historical Review      Few things rest in isolation from historical precedent. Historical reviews are focused on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomenon emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review      A review does not always focus on what someone said [content], but how they said it [method of analysis]. This approach provides a framework of understanding at different levels (i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques), enables researchers to draw on a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection and data analysis, and helps highlight many ethical issues which we should be aware of and consider as we go through our study.

Systematic Review      This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?"

Theoretical Review      The purpose of this form is to concretely examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomenon. The theoretical literature review help establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

* Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147.

All content is from The Literature Review created by Dr. Robert Larabee USC

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Literature Reviews

• Getting Started

Selecting a Review Type

Defining the scope of your review, four common types of reviews.

• Developing a Research Question
• Searching the Literature
• Searching Tips
• ChatGPT [beta]
• Documenting your Search
• Using Citation Managers
• Concept Mapping
• Writing the Review
• Further Resources

More Review Types

This article by Sutton & Booth (2019) explores 48 distinct types of Literature Reviews:

Which Review is Right for You?

The  Right Review tool  has questions about your lit review process and plans. It offers a qualitative and quantitative option. At completion, you are given a lit review type recommendation.

You'll want to think about the kind of review you are doing. Is it a selective or comprehensive review? Is the review part of a larger work or a stand-alone work ?

For example, if you're writing the Literature Review section of a journal article, that's a selective review which is part of a larger work. Alternatively, if you're writing a review article, that's a comprehensive review which is a stand-alone work. Thinking about this will help you develop the scope of the review.

This exercise will help define the scope of your Literature Review, setting the boundaries for which literature to include and which to exclude.

A FEW GENERAL CONSIDERATIONS WHEN DEFINING SCOPE

• Which populations to investigate — this can include gender, age, socio-economic status, race, geographic location, etc., if the research area includes humans.
• What years to include — if researching the legalization of medicinal cannabis, you might only look at the previous 20 years; but if researching dolphin mating practices, you might extend many more decades.
• Which subject areas — if researching artificial intelligence, subject areas could be computer science, robotics, or health sciences
• How many sources  — a selective review for a class assignment might only need ten, while a comprehensive review for a dissertation might include hundreds. There is no one right answer.
• There will be many other considerations that are more specific to your topic. 

Most databases will allow you to limit years and subject areas, so look for those tools while searching. See the Searching Tips tab for information on how use these tools.

LITERATURE REVIEW

• Often used as a generic term to describe any type of review
• More precise definition:  Published materials that provide an examination of published literature . Can cover wide range of subjects at various levels of comprehensiveness.
• Identifies gaps in research, explains importance of topic, hypothesizes future work, etc.
• Usually written as part of a larger work like a journal article or dissertation

SCOPING REVIEW

• Conducted to address broad research questions with the goal of understanding the extent of research that has been conducted.
• Provides a preliminary assessment of the potential size and scope of available research literature. It aims to identify the nature and extent of research evidence (usually including ongoing research) 
• Doesn't assess the quality of the literature gathered (i.e. presence of literature on a topic shouldn’t be conflated w/ the quality of that literature)
• " Preparing scoping reviews for publication using methodological guides and reporting standards " is a great article to read on Scoping Reviews

SYSTEMATIC REVIEW

• Common in the health sciences ( Taubman Health Sciences Library guide to Systematic Reviews )
• Goal: collect all literature that meets specific criteria (methodology, population, treatment, etc.) and then appraise its quality and synthesize it
• Follows strict protocol for literature collection, appraisal and synthesis
• Typically performed by research teams 
• Takes 12-18 months to complete
• Often written as a stand alone work

META-ANALYSIS

• Goes one step further than a systematic review by statistically combining the results of quantitative studies to provide a more precise effect of the results. 
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• URL: https://guides.lib.umich.edu/litreview

Completing A Literature Review

• What is a Literature Review?

Types of Literature Review

• Tips for Conducting a Literature Review
• Developing a Search Strategy
• Tips for Writing your Literature Review

Help with your Literature Review

The library has a Moodle module that has lots of tutorials on academic skills such as searching, writing and referencing. 

Types of literature review

Sometimes it can be useful to pick a 'type' of literature review to help you structure your work. Your choice of review type will depend upon a number of different factors including the purpose of the review, subject area, and the research question. 

Below is a brief overview of some popular types of literature review. 

• Argumentative Reviews  involve using selective information to support one side of an argument.  This type of review can also be used to refute an argument or an established point of view. It is worth noting that bias can be a feature of this type of review.
• Historical Reviews  identify and trace how things were done in the past, mapping changes in theory, processes, etc. It also places research within historical context.
• Integrative Reviews  bring new perspective to an existing body of literature. This involves critically evaluating and synthesising secondary data to create new perspectives.  This type of review can be used when the researcher is not collecting or analysing their own data (primary data).
•  Mapping Reviews are similar to a scoping review (see below) but focus on a specific question not a topic.
•  Methodological Reviews examine how research was conducted.  This type of review often involves reviewing the entire research design process, from philosophy to methodology, data collection methods and data analysis. 
• Narrative Reviews  involve summarising and critically evaluating information within a body of knowledge.  It allows researchers to draw conclusions and to identify gaps within the literature.  You will need to have a clearly defined research question in order to undertake a narrative review. 
• Scoping Reviews provide a "preliminary assessment of potential size and scope of available research literature.  [The] aim is to identify the nature and extent of research evidence (usually including ongoing research).”  Grant & Booth  “A typology of reviews: an analysis of 14 review types and associated methodologies”.  Health Information & Libraries Journal.  May, 2009.
• Systematic Reviews involve doing an exhaustive review of a topic with the purpose of answering a question or solving a problem. Systematic reviews are conducted according to a strict selection and evaluation criteria. These reviews seek to identify relationships and patterns from which conclusions can be drawn.
• Theoretical Reviews  attempt to identify existing theories or highlight a lack of adequate theory within a subject area. This type of review can also examine how well a particular theory has been tested.
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• Next: Tips for Conducting a Literature Review >>
• Last Updated: Jul 24, 2023 2:08 PM
• URL: https://tudublin.libguides.com/c.php?g=696293

University Libraries

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Evidence-based Practice in Healthcare

• Performing a Literature Review
• EBP Tutorials
• Question- PICO
• Definitions
• Systematic Reviews
• Levels of Evidence
• Finding Evidence
• Filter by Study Type
• Too Much or Too Little?
• Critical Appraisal
• Quality Improvement (QI)
• Contact - Need Help?

Hanna's Performing a qualitity literature review presentation slides

• Link to the PPT slides via OneDrive anyone can view

Characteristics of a Good Literature Review in Health & Medicine

Clear Objectives and Research Questions : The review should start with clearly defined objectives and research questions that guide the scope and focus of the review.

Comprehensive Coverage : Include a wide range of relevant sources, such as research articles, review papers, clinical guidelines, and books. Aim for a broad understanding of the topic, covering historical developments and current advancements. To do this, an intentional and minimally biased search strategy.

• Link to relevant databases to consider for a comprehensive search (search 2+ databases)
• Link to the video "Searching your Topic: Strategies and Efficiencies" by Hanna Schmillen
• Link to the worksheet "From topic, to PICO, to search strategy" to help researchers work through their topic into an intentional search strategy by Hanna Schmillen

Transparency and Replicability : The review process, search strategy, should be transparent, with detailed documentation of all steps taken. This allows others to replicate the review or update it in the future.

Appraisal of Studies Included : Each included study should be critically appraised for methodological quality and relevance. Use standardized appraisal tools to assess the risk of bias and the quality of evidence.

• Link to the video " Evaluating Health Research" by Hanna Schmillen
• Link to evaluating and appraising studies tab, which includes a rubric and checklists

Clear Synthesis and Discussion of Findings : The review should provide a thorough discussion of the findings, including any patterns, relationships, or trends identified in the literature. Address the strengths and limitations of the reviewed studies and the review itself. Present findings in a balanced and unbiased manner, avoiding over interpretation or selective reporting of results.

Implications for Practice and Research : The review should highlight the practical implications of the findings for medical practice and policy. It should also identify gaps in the current literature and suggest areas for future research.

Referencing and Citation : Use proper citation practices to credit original sources. Provide a comprehensive reference list to guide readers to the original studies.

• Link to Citation Style Guide, includes tab about Zotero

Note: A literature review is not a systematic review. For more information about systematic reviews and different types of evidence synthesis projects, see the Evidence Synthesis guide .

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ON YOUR 1ST ORDER

Different Types of Literature Review: Which One Fits Your Research?

By Laura Brown on 13th October 2023

You might not have heard that there are multiple kinds of literature review. However, with the progress in your academic career you will learn these classifications and may need to use different types of them. However, there is nothing to worry if you aren’t aware of them now, as here we are going to discuss this topic in detail.

There are approximately 14 types of literature review on the basis of their specific objectives, methodologies, and the way they approach and analyse existing literature in academic research. Of those 14, there are 4 major types. But before we delve into the details of each one of them and how they are useful in academics, let’s first understand the basics of literature review.

What is Literature Review?

A literature review is a critical and systematic summary and evaluation of existing research. It is an essential component of academic and research work, providing an overview of the current state of knowledge in a particular field.

In easy words, a literature review is like making a big, organised summary of all the important research and smart books or articles about a particular topic or question. It’s something scholars and researchers do, and it helps everyone see what we already know about that topic. It’s kind of like taking a snapshot of what we understand right now in a certain field.

It serves with some specific purpose in the research.

• Provides a comprehensive understanding of existing research on a topic.
• Identifies gaps, trends, and inconsistencies in the literature.
• Contextualise your own research within the broader academic discourse.
• Supports the development of theoretical frameworks or research hypotheses.

4 Major Types Of Literature Review

The four major types include, Narrative Review, Systematic Review, Meta-Analysis, and Scoping Review. These are known as the major ones because they’re like the “go-to” methods for researchers in academic and research circles. Think of them as the classic tools in the researcher’s toolbox. They’ve earned their reputation because they have a unique style for literature review introduction , clear steps and specific qualities that make them super handy for different research needs.

1. Narrative Review

Narrative reviews present a well-structured narrative that reads like a cohesive story, providing a comprehensive overview of a specific topic. These reviews often incorporate historical context and offer a broad understanding of the subject matter, making them valuable for researchers looking to establish a foundational understanding of their area of interest. They are particularly useful when a historical perspective or a broad context is necessary to comprehend the current state of knowledge in a field.

2. Systematic Review

Systematic reviews are renowned for their methodological rigour. They involve a meticulously structured process that includes the systematic selection of relevant studies, comprehensive data extraction, and a critical synthesis of their findings. This systematic approach is designed to minimise bias and subjectivity, making systematic reviews highly reliable and objective. They are considered the gold standard for evidence-based research as they provide a clear and rigorous assessment of the available evidence on a specific research question.

3. Meta Analysis

Meta analysis is a powerful method for researchers who prefer a quantitative and statistical perspective. It involves the statistical synthesis of data from various studies, allowing researchers to draw more precise and generalisable conclusions by combining data from multiple sources. Meta analyses are especially valuable when the aim is to quantitatively measure the effect size or impact of a particular intervention, treatment, or phenomenon.

4. Scoping Review

Scoping reviews are invaluable tools, especially for researchers in the early stages of exploring a topic. These reviews aim to map the existing literature, identifying gaps and helping clarify research questions. Scoping reviews provide a panoramic view of the available research, which is particularly useful when researchers are embarking on exploratory studies or trying to understand the breadth and depth of a subject before conducting more focused research.

Different Types Of Literature review In Research

There are some more approaches to conduct literature review. Let’s explore these classifications quickly.

5. Critical Review

Critical reviews provide an in-depth evaluation of existing literature, scrutinising sources for their strengths, weaknesses, and relevance. They offer a critical perspective, often highlighting gaps in the research and areas for further investigation.

6. Theoretical Review

Theoretical reviews are centred around exploring and analysing the theoretical frameworks, concepts, and models present in the literature. They aim to contribute to the development and refinement of theoretical perspectives within a specific field.

7. Integrative Review

Integrative reviews synthesise a diverse range of studies, drawing connections between various research findings to create a comprehensive understanding of a topic. These reviews often bridge gaps between different perspectives and provide a holistic overview.

8. Historical Review

Historical reviews focus on the evolution of a topic over time, tracing its development through past research, events, and scholarly contributions. They offer valuable context for understanding the current state of research.

9. Methodological Review

Among the different kinds of literature reviews, methodological reviews delve into the research methods and methodologies employed in existing studies. Researchers assess these approaches for their effectiveness, validity, and relevance to the research question at hand.

10. Cross-Disciplinary Review

Cross-disciplinary reviews explore a topic from multiple academic disciplines, emphasising the diversity of perspectives and insights that each discipline brings. They are particularly useful for interdisciplinary research projects and uncovering connections between seemingly unrelated fields.

11. Descriptive Review

Descriptive reviews provide an organised summary of existing literature without extensive analysis. They offer a straightforward overview of key findings, research methods, and themes present in the reviewed studies.

12. Rapid Review

Rapid reviews expedite the literature review process, focusing on summarising relevant studies quickly. They are often used for time-sensitive projects where efficiency is a priority, without sacrificing quality.

13. Conceptual Review

Conceptual reviews concentrate on clarifying and developing theoretical concepts within a specific field. They address ambiguities or inconsistencies in existing theories, aiming to refine and expand conceptual frameworks.

14. Library Research

Library research reviews rely primarily on library and archival resources to gather and synthesise information. They are often employed in historical or archive-based research projects, utilising library collections and historical documents for in-depth analysis.

Each type of literature review serves distinct purposes and comes with its own set of strengths and weaknesses, allowing researchers to choose the one that best suits their research objectives and questions.

Choosing the Ideal Literature Review Approach in Academics

In order to conduct your research in the right manner, it is important that you choose the correct type of review for your literature. Here are 8 amazing tips we have sorted for you in regard to literature review help so that you can select the best-suited type for your research.

• Clarify Your Research Goals: Begin by defining your research objectives and what you aim to achieve with the literature review. Are you looking to summarise existing knowledge, identify gaps, or analyse specific data?
• Understand Different Review Types: Familiarise yourself with different kinds of literature reviews, including systematic reviews, narrative reviews, meta-analyses, scoping reviews, and integrative reviews. Each serves a different purpose.
• Consider Available Resources: Assess the resources at your disposal, including time, access to databases, and the volume of literature on your topic. Some review types may be more resource-intensive than others.
• Alignment with Research Question: Ensure that the chosen review type aligns with your research question or hypothesis. Some types are better suited for answering specific research questions than others.
• Scope and Depth: Determine the scope and depth of your review. For a broad overview, a narrative review might be suitable, while a systematic review is ideal for an in-depth analysis.
• Consult with Advisors: Seek guidance from your academic advisors or mentors. They can provide valuable insights into which review type best fits your research goals and resources.
• Consider Research Field Standards: Different academic fields have established standards and preferences for different forms of literature review. Familiarise yourself with what is common and accepted in your field.
• Pilot Review: Consider conducting a small-scale pilot review of the literature to test the feasibility and suitability of your chosen review type before committing to a larger project.

Bonus Tip: Crafting an Effective Literature Review

Now, since you have learned all the literature review types and have understood which one to prefer, here are some bonus tips for you to structure a literature review of a dissertation .

• Clearly Define Your Research Question: Start with a well-defined and focused research question to guide your literature review.
• Thorough Search Strategy: Develop a comprehensive search strategy to ensure you capture all relevant literature.
• Critical Evaluation: Assess the quality and credibility of the sources you include in your review.
• Synthesise and Organise: Summarise the key findings and organise the literature into themes or categories.
• Maintain a Systematic Approach: If conducting a systematic review, adhere to a predefined methodology and reporting guidelines.
• Engage in Continuous Review: Regularly update your literature review to incorporate new research and maintain relevance.

Some Useful Tools And Resources For You

Effective literature reviews demand a range of tools and resources to streamline the process.

• Reference management software like EndNote, Zotero, and Mendeley helps organise, store, and cite sources, saving time and ensuring accuracy.
• Academic databases such as PubMed, Google Scholar, and Web of Science provide access to a vast array of scholarly articles, with advanced search and citation tracking features.
• Research guides from universities and libraries offer tips and templates for structuring reviews.
• Research networks like ResearchGate and Academia.edu facilitate collaboration and access to publications. Literature review templates and research workshops provide additional support.

Some Common Mistakes To Avoid

Avoid these common mistakes when crafting literature reviews.

• Unclear research objectives result in unfocused reviews, so start with well-defined questions.
• Biased source selection can compromise objectivity, so include diverse perspectives.
• Never miss on referencing; proper citation and referencing are essential for academic integrity.
• Don’t overlook older literature, which provides foundational insights.
• Be mindful of scope creep, where the review drifts from the research question; stay disciplined to maintain focus and relevance.

While Summing Up On Various Types Of Literature Review

As we conclude this classification of fourteen distinct approaches to conduct literature reviews, it’s clear that the world of research offers a multitude of avenues for understanding, analysing, and contributing to existing knowledge.

Whether you’re a seasoned scholar or a student beginning your academic journey, the choice of review type should align with your research objectives and the nature of your topic. The versatility of these approaches empowers you to tailor your review to the demands of your project.

Remember, your research endeavours have the potential to shape the future of knowledge, so choose wisely and dive into the world of literature reviews with confidence and purpose. Happy reviewing!

Laura Brown, a senior content writer who writes actionable blogs at Crowd Writer.

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Types of reviews.

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Not sure what type of review you want to conduct?

There are many types of reviews ---  narrative reviews ,  scoping reviews , systematic reviews, integrative reviews, umbrella reviews, rapid reviews and others --- and it's not always straightforward to choose which type of review to conduct. These Review Navigator tools (see below) ask a series of questions to guide you through the various kinds of reviews and to help you determine the best choice for your research needs.

• Which review is right for you? (Univ. of Manitoba)
• What type of review is right for you? (Cornell)
• Review Ready Reckoner - Assessment Tool (RRRsAT)
• A typology of reviews: an analysis of 14 review types and associated methodologies. by Grant & Booth
• Meeting the review family: exploring review types and associated information retrieval requirements | Health Info Libr J, 2019

Reproduced from Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies . Health Info Libr J. 2009 Jun;26(2):91-108. doi: 10.1111/j.1471-1842.2009.00848.x

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• About Covidence and systematic reviews

What are the different types of review?

Systematic literature reviews (slrs).

SLR’s attempt to collate all empirical evidence that fit pre-specified eligibility criteria in order to answer a specific clearly-formulated research question.  A SLR uses explicit and reproducible systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made.

The process starts with a research question and a protocol or research plan. A review team searches for studies to answer the question using a highly sensitive search strategy. The retrieved studies are then screened for eligibility using pre-specified inclusion and exclusion criteria (this is done by at least two people working independently). Next, the reviewers extract the relevant data and assess the quality of the included studies. Finally, the review team synthesizes the extracted study data and presents the results. 

A SLR may contain meta-analyses (statistical analysis). A SLR which is continually updated, incorporating relevant new evidence as it becomes available is often known as a living SLR.

Rapid reviews

Rapid reviews aim to produce a rigorous synthesis quickly (due to time constraints/urgency), based on a pre-defined research question. The review process for rapid reviews is the same as for a more traditional systematic review: the emphasis is on a replicable pre-specified search, and screening methods that minimize the risk of bias, although potentially isn’t as stringent as a formal systematic review.

The process operates within pre-specified limits (for example, by restricting searches to articles published during a specific timeframe) and is usually run by a multidisciplinary team with expertise in systematic review methods.

Umbrella reviews or Overview of reviews

An umbrella review is a review of multiple systematic reviews. The process uses explicit and systematic methods to search for, and identify, systematic reviews on related research questions in the same topic area. The purpose of an umbrella review is to synthesize the results of the systematic reviews across important outcomes. 

Scoping reviews

Scoping reviews are exploratory and they typically address a broad question, compared to a systematic review that typically has a more targeted question. 

Researchers conduct scoping reviews to assess the extent of the available evidence, to organize it into groups and to highlight gaps. If a scoping review finds no studies, this might help researchers to decide that a systematic review is likely to be of limited value and that resources could be better directed elsewhere.

Literature reviews or narrative reviews

Literature, or narrative, reviews provide an overview of what is known about a particular topic. They evaluate the material, rather than simply restating it, but the methods used to do this are not usually prespecified and they are not described in detail in the review. The search might be comprehensive but it does not aim to be exhaustive. Literature reviews are often topic based  and can take the form of a discussion. Literature reviews lack precision and replicability and can  present their findings in the context of what has come before. Often, this sort of synthesis does not attempt to control for the author’s own bias. The results or conclusion of a literature review is likely to be presented in a narrative format rather than statistical methods.

Take a look at the articles about the different types of review on the Covidence blog:

• Systematic review types: meet the family
• The difference between a systematic review and a literature review
• The difference between a systematic review and a meta-analysis

Type III Vasa Previa Associated with Resolution of a Low-Lying Placenta: Case Report and Literature Review

Affiliations.

• 1 Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, Ontario, Canada.
• 2 Department of Obstetrics and Gynaecology, Queen's University, Kingston, Ontario, Canada.
• PMID: 38736707
• PMCID: PMC11087141
• DOI: 10.1055/a-2315-7550

Vasa previa occurs when fetal vessels lie above the cervical os. A novel type of vasa previa, known as type III, is characterized by an abnormal branching of fetal vessels from the placenta in the absence of velamentous cord insertion (as seen in type I) or multilobed placenta (as seen in type II). Here, we present a case of a type III vasa previa after a resolution of a low-lying placenta. The presence of any known risk factors of vasa previa, including low-lying placenta, should prompt screening for vasa previa in the third trimester. Accurate and timely diagnosis of vasa previa will confer significant survival benefit for the neonate.

Keywords: fetal medicine; placenta; prenatal diagnosis; vasa previa.

The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).

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Mini review article, acute complicated jejunum diverticulitis: a case report with a short literature review.

• 1 Department of Surgery, Iuliu Hațieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
• 2 Department of Surgery, Emergency Clinical County Hospital, Cluj-Napoca, Romania
• 3 Internal Medicine Department, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
• 4 Department of Internal Medicine, Emergency Clinical County Hospital, Cluj-Napoca, Romania
• 5 Department of Hematology, Oncology Institute "Prof. Dr. Ion Chiricuta ", Cluj-Napoca, Romania

Introduction: Jejunal diverticulosis is a rare condition. Most of the time, it is asymptomatic; but it can cause severe complications such as intestinal perforation, mechanical occlusion, and hemorrhage.

Case presentation: A patient aged 78 years, with a history of biological aortic valve prosthesis, atrial fibrillation, type 2 diabetes mellitus, and chronic obstructive pulmonary disease, presented in the emergency department for acute abdominal pain in the lower abdominal floor, nausea, and inappetence. Abdominal computed tomography revealed an inflammatory block in the hypogastrium, agglutinated small intestinal loops, fecal stasis, and air inclusions. Pulled mesentery and associated internal hernia are suspected. Exploratory laparotomy was performed, revealing an inflammatory block in the hypogastrium, whose dissection revealed inner purulent collection and the appearance of jejunal diverticulitis, a diagnosis confirmed by histopathological examination. Segmental resection of the jejunum with double-layer terminal–terminal enteroenteric anastomosis, lavage, and drainage was performed. The evolution was favorable.

Conclusion: Based on our brief review, the diagnosis of complicated jejunal diverticulosis is difficult and sometimes not accurately established, even by high-resolution imaging techniques, with diagnostic laparotomy being necessary for these situations. Surgical treatment should be considered before severe complications develop.

1 Introduction

Jejunal diverticulosis is a rare pathology that occurs in 0.3–1.3% of patients ( 1 ). Most often, it is asymptomatic; but sometimes it can give serious complications such as diverticulitis, perforation, mechanical occlusion, and hemorrhage. Due to its position, most of the time, high-evolution imaging techniques cannot establish the diagnosis. Therefore, this diagnosis should be considered in patients with intense abdominal pain localized periumbilically or in the hypogastrium. Performing an emergency laparoscopy is preferable to a conservative medical attitude in these situations. We present the case of a 78-year-old woman who presented with a complication of small intestine diverticulosis – diverticulitis and intestinal perforation requiring emergency surgery.

This paper aims to describe a case of small intestine diverticulitis and intestinal perforation and review the cases of small intestine diverticulitis published in the last 10 years to determine the best method of diagnosis and appropriate conservative or surgical treatment for these cases.

2 Case presentation

A 78-year-old female patient was referred to our emergency department with complaints of lower abdominal pain, slowed gastrointestinal transit, nausea, loss of appetite, and fatigue.

Her medical history was significant for hypertension, biological aortic valve, mitral valve regurgitation, atrial fibrillation, heart failure NYHA II/III, chronic obstructive pulmonary disease Gold II, type 2 diabetes mellitus, and dyslipidemia. There was no relevant family history. Her medication history consisted of Perindopril 10 mg/Indapamide 2.5 mg, Acenocoumarol 2 mg/day, Digoxin 0.25 mg/day, 5/7 days, Budesonide 160 microg/Formoterol 4.5 micron 2× two puffs/day, and Metformin 1,000 mg/day.

The pain was moderate without irradiation. There were no aggravating or relieving factors. The symptoms were worsening in the last 4 days before admission.

On admission, the patient had a body temperature of 37.7°C, a pulse rate of 80 beats/min, a blood pressure of 140/80 mmHg, and a saturation of 96% in ambient air. Physical examination revealed a new periumbilical mass associated with lower abdominal tenderness but no rigidity or rebound tenderness.

Blood tests showed leukocytosis (22 × 109/L), neutrophilia (20.09 × 109/L), C-reactive protein >30 mg/dL, procalcitonin 9.5 ng/mL, creatinine = 3.42 mg/dL, urea = 127 mg/dL, and INR > 9.

An abdominal ultrasound was performed, which revealed intestinal loops with peristalsis present at the level of the descending colon – a slightly dilated intestinal loop with a slightly thickened intestinal wall. We completed with abdominal and pelvic computer tomography scan (CT), which showed an inflammatory block at the level of the hypogastrium – thin intestinal loops, agglutinated, forming a lesional block of 90/69/60 mm, with fecal stasis and air inclusions. Adjacent fat infiltrated, with multiple fluid fuses present. Pulled mesentery and mesenteric vessels – an associated internal hernia is suspected ( Figure 1 ).

Figure 1 . CT, coronal (A) , axial (B) , and sagittal section (C) inflammatory block marked with a yellow arrow.

An echocardiogram reported neurofunctional biological aortic valve, concentric left ventricular hypertrophy, and mitral valve regurgitation. There were no vegetations of valves observed.

Due to high suspicion of intestinal subocclusion, the patient underwent exploratory laparotomy via a median incision. The abdominal cavity was explored, detecting an epigastric inflammatory block that includes several loops of the small intestine (jejunum and ileum) and omentum, the dissection of which reveals the minimal interileal purulent collection and a tumor at about 50 cm from the duodenojejunal angle, with the appearance of diverticulitis. At 40 cm from the duodenojejunal angle, another uncomplicated intestinal diverticulum of about 2 cm diameter is identified ( Figure 2 ).

Figure 2 . (A–C) Intraoperative appearance. Intestinal inflammatory block, the dissection of which reveals an abscessed jejunal diverticulum.

We performed segmental resection of the jejunum with terminal–terminal enteroenteric anastomosis.

in a double layer, lavage, and drainage. IV fluids, Ceftriaxone 2 g/day once daily, Metronidazole 500 mg every 8 h, probiotics, and Famotidine 20 mg were administered. The treatment of associated diseases continued.

On Day 4, the patient had normal gastrointestinal transit. During hospitalization, the patient presented one episode of upper gastrointestinal bleeding. The patient underwent an esogastroduodenal endoscopy, which revealed a Forrest III antral gastric ulcer and congestive corporeal gastritis without an active source of bleeding. Under treatment with proton pump inhibitors, erythrocyte mass transfusion evolution was favorable. The patient was discharged home on day 21.

Histopathological examination confirmed the diagnosis of jejunal diverticulitis. Stasis, hemorrhagic areas, and lymphoid follicles were observed at the resection margins. The intestinal wall shows areas of necrosis spread throughout its thickness, hemorrhagic areas, abscesses, and a marked transparietal predominantly neutrophilic inflammatory infiltrate. At the level of the diverticulum, fibrin–hematic exudate is observed at the level of the serosa, vascular stasis, hemorrhagic areas, and mixed inflammatory infiltrate, with the presence of lymphoid follicles and erosions at the level of the mucosa ( Figures 1 , 2 ).

3 Discussion

Diverticula are hernias of the mucosa and submucosa through the muscular layer of the intestinal wall. It is usually located in the sigmoid and descending colon ( 1 ).

Localization in the small intestine is rare; the incidence varies between 0.5 and 2.3%. It is usually identified at the level of the proximal jejunum (75%), with the ileum being identified only in 5% of cases ( 1 ). Jejunal diverticula are usually multiple and occur more frequently in men in the sixth or seventh decade ( 2 , 3 ).

Diverticula form in the intestinal wall, in areas of low resistance, due to increased intraluminal pressure ( 4 ). They may have a genetic determinism that should be suspected, especially in the case of diffuse forms ( 5 , 6 ). It is located more frequently in the jejunum than the ileum because the penetrating jejunal arteries have a larger diameter. Other favorable factors for the appearance of diverticles are dysmotility and abnormalities in the mesenteric plex ( 1 , 4 ). They differ from Merkel diverticula, because they appear on the mesenteric margin ( 1 ).

Clinically, jejunal diverticulosis is usually asymptomatic (80%) of cases. When it is symptomatic, it is manifested by nonspecific abdominal pain, transit disorders (diarrhea/constipation), and flatulence ( 1 , 7 ). Complications of jejunal diverticulosis occur in about 10% of cases, most commonly consisting of acute diverticulitis, mechanical obstruction, volvulus, perforation, peritonitis, and hemorrhage ( 1 , 4 ). Perforation with peritonitis can be caused by an inflammatory diverticulum or a ruptured diverticular abscess, as was the case with our patient.

Because of its nonspecific symptoms and because it is rare, jejunal diverticulitis is often misinterpreted as appendicitis, peptic ulcer, cholecystitis, Crohn’s disease, or colonic diverticulitis ( 8 ). To avoid misdiagnosis, which inevitably leads to delayed treatment, clinicians should be aware of this entity.

Abdominal ultrasonography is used to establish the diagnosis at the first stage. This can sometimes indicate a thickened intestinal wall, irregular-looking formations related to the intestine, hypoechogenic having a hyperechogenic center – characteristic aspect for diverticula, and hyperechogenic tissue around these formations, indicating infiltration of surrounding fat or air bubbles ( 9 ).

Computed tomography (CT) is more sensitive in the diagnosis of acute diverticulitis and its complications compared to abdominal ultrasound and is therefore preferred ( 1 , 10 ).

CT scans identify diverticular inflammation characterized by peridiverticular edema and thickening of the diverticular wall ( 8 ). The presence of pneumoperitoneum is not a definite sign of peritonitis, because the thin wall of the diverticulum can allow air to pass through ( 9 ).

CT diagnosis is difficult and remains uncertain in advanced local forms, in which diverticula can no longer be identified due to extensive local inflammation that causes fluid and gaseous infiltration. Highlighting other diverticula on the mesenteric edge of the loop of the small intestine helps clarify the diagnosis ( 9 ).

Selective mesenteric angiography or CT angiography may be used to locate active bleeding in cases of jejunal diverticular hemorrhage ( 11 ).

Treatment of diverticulitis can be conservative and medical (antibiotic therapy, according to table) ( 10 ).

The most common bacterial etiology of diverticulitis are:

1. Enterobacteriaceae: Escherichia coli , Klebsiella sp., aerobic high gram-negative bacillus.

2. Bacteroides species.

3. Enterococcus species: Enterococcus faecalis most common, Enterococcus faecium.

4. Pseudomonas aeruginosa : 3–15% ( 12 ) (see Table 1 ).

Table 1 . Antibiotic treatment in case of acute diverticulitis ( 12 ).

The average duration of antibiotic treatment is 5–10 days. The criteria for discontinuing treatment are clinical improvement, normalization of leukocytes, and resumption of intestinal transit ( 12 ).

In the case of localized limited perforation, conservative management treatment may be indicated in hemodynamically stable patients ( 4 , 7 ), with the caveat that surgery should be performed if clinical improvement is not achieved within 48–72 h. In patients with peridiverticular abscess, antibiotic treatment and image-guided drainage (CT) may theoretically be sufficient, depending on the size of the collection and the possibility of a percutaneous approach ( 8 ).

For perforated jejunal diverticula, with peritonitis, or in the case of abuse or significant bleeding, literature data recommend emergency laparotomy, segmental intestinal resection, and primary anastomosis to avoid complications ( 13 ). Resection should be limited to the intestinal loop with complicated diverticulum (local abscess, peritonitis, or bleeding) to prevent short bowel syndrome ( 4 , 11 ). An exception is pan-jejunoileal diverticulosis, for which conservative treatment may be preferred. This is because surgery can lead to severe malnutrition ( 3 ).

Risk factors for unfavorable evolution are old age, comorbidities, delay in diagnosis, and duration interval between perforation and surgery ( 9 ).

No consensus exists on the therapeutic strategy and management of jejunales diverticulitis ( 8 ).

To determine the best diagnostic method for complicated jejunal diverticulitis and the most appropriate treatment, we searched PubMed, MedNar, and Cochrane Library electronic databases for literature reviews on cases of jejunal diverticulitis published between 1.01.2014 and 31.12.2023. We considered the following terms in the studies’ title or abstract: “jejunal diverticulitis.” We excluded studies in languages other than English and French and excluded articles that did not cover several cases. The results are summarized in Table 2 .

Table 2 . Management of patients with acute diverticulitis according to specialized reviews from 2014–2023.

As Table 2 shows, a CT scan is more sensitive in diagnosing acute diverticulitis, but angiography is used in cases of gastrointestinal bleeding. Sometimes, exploratory laparoscopy is needed for diagnosis.

Thus, surgical treatment remains the management of choice in patients with jejunal diverticulitis, possibly due to late diagnosis in the complication phase ( 8 ).

In our case, due to advanced local inflammation, the diagnosis could not be established correctly by CT, and the abscessed and perforated intestinal diverticulum was misinterpreted as an internal hernia with intestinal occlusion. It was necessary to perform a laparotomy for diagnostic purposes and surgical treatment. The postoperative evolution was favorable, although the patient had an increased surgical risk of presenting multiple comorbidities.

4 Conclusion

Diagnosing complicated jejunal diverticulosis is complex and sometimes not accurately established, even by high-resolution imaging, such as a CT scan, the more sensitive diagnostic technique. Diagnostic laparotomy is necessary in these situations. Surgical treatment should be considered in complicated jejunal diverticulitis before severe complications develop.

Author contributions

SC: Writing – original draft, Writing – review & editing, Investigation, Methodology. MM: Conceptualization, Supervision, Writing – original draft, Writing – review & editing. MS: Investigation, Writing – original draft, Writing – review & editing. FM: Investigation, Methodology, Writing – original draft, Writing – review & editing. RC: Writing – original draft, Writing – review & editing.

The author(s) declare that financial support was received for this article’s research, authorship, and publication. The publication fees were partially reimbursed by the University of Medicine and Pharmacy, Cluj-Napoca, Romania.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

1. Pajtak, R, Ramadan, A, and Strauss, P. Strangulated diverticulum: a new acute complication of small bowel diverticulosis. J Surg Case Rep . (2023) 5:rjad253. doi: 10.1093/jscr/rjad253

Crossref Full Text | Google Scholar

2. Karas, L, Asif, M, Chun, V, and Khan, FA. Complicated small bowel diverticular disease: a case series. BMJ Case Rep . (2017) 2017:bcr2017219699. doi: 10.1136/bcr-2017-219699

3. Prough, H, Jaffe, S, and Jones, B. Jejunal Diverticulitis. J Surg Case Rep . (2019) 1:rjz005. doi: 10.1093/jscr/rjz005

4. Khan, M, Arshad, R, Malik, I, Kamran, A, Gul, F, and Lee, KY. Jejunal diverticulosis presenting as intestinal obstruction - a case report of a rare association. Clin Case Rep . (2023) 11:e7033. doi: 10.1002/ccr3.7033

5. Scheese, D, Alwatari, Y, Khan, J, and Slaughter, A. Complicated jejunal diverticulitis: a case report and review of literature. Clin Case Reports . (2022) 10:e657011. doi: 10.1002/ccr3.6570

6. Barbaro, MR, Cremon, C, Fuschi, D, Marasco, G, Palombo, M, Stanghellini, V, et al. Pathophysiology of diverticular disease: from diverticula formation to symptom generation. Int J Mol Sci . (2022) 23:6698. doi: 10.3390/ijms23126698

7. Khsiba, A, Bradai, S, Mahmoudi, M, Mohamed, AB, Bradai, J, Bouzaidi, K, et al. Jejunal diverticulitis as a rare cause of abdominal pain: a case report. Pan Afr Med J . (2022) 17:222. doi: 10.11604/pamj.2022.41.222.29095

8. Zafouri, EB, Ben Ismail, I, Sghaier, M, Rebii, S, and Zoghlami, A. Jejunal diverticulitis: a new case report and a literature review. Int J Surg Case Rep . (2022) 97:107395. doi: 10.1016/j.ijscr.2022.107395

9. Lebert, P, Ernst, O, and Zins, M. Acquired diverticular disease of the jejunum and ileum: imaging features and pitfalls. Abdom. Radiol. (2019) 44:1734–43. doi: 10.1007/s00261-019-01928-1

PubMed Abstract | Crossref Full Text | Google Scholar

10. Rangan, V, and Lamont, JT. Small bowel diverticulosis: pathogenesis, clinical management, and new concepts. Curr Gastroenterol Rep . (2022) 22:4. doi: 10.1007/s11894-019-0741-2

11. Lin, CH, Hsieh, HF, Yu, CY, Yu, JC, Chan, DC, Chen, TW, et al. Diverticulosis of the jejunum with intestinal 5416Obstruction: a case report. World J Gastroenterol . (2005) 11:5416. doi: 10.3748/wjg.v11.i34.5416

12. CDC. Antibiotic Use in the United States, 2020 Update: Progress and Opportunities. Atlanta, GA: US Department of Health and Human Services, CDC , (2021)

Google Scholar

13. Ng, ZQ, Theophilus, M, Navadgi, S, Menon, T, and Wijesuriya, R. Jejunal diverticulitis: a single-Center experience and proposed management algorithm. Surg Infect . (2019) 20:499–503. doi: 10.1089/sur.2019.070

14. Johnson, KN, Fankhauser, GT, Chapital, AB, Merritt, MV, and Johnson, DJ. Emergency management of complicated jejunal diverticulosis. Am Surg . (2014) 80:600–3. doi: 10.1177/000313481408000625

15. Horesh, N, Klang, E, Gravetz, A, Nevo, Y, Amiel, I, Amitai, MM, et al. Jejunal Diverticulitis. J Laparoendosc Adv Surg Tech A . (2016) 26:596–9. doi: 10.1089/lap.2016.0066

16. Kumar, D . Complicated jejunal diverticulitis with unusual presentation. Radiol Case Rep . (2018) 13:58–64. doi: 10.1016/j.radcr.2017.10.002

17. De Simone, B, Alberici, L, Ansaloni, L, Sartelli, M, Coccolini, F, and Catena, F. Not all diverticulites are colonic: small bowel diverticulitis - a systematic review. Minerva Chir . (2019) 74:137–45. doi: 10.23736/S0026-4733.18.07745-3

18. López Marcano, AJ, Ramia, JM, De la Plaza, LR, Alonso, S, Gonzales Aguilar, JD, and Kühnhardt Barrantes, AW. Complicated jejunoileal diverticular disease: a 12 cases' serie and literature review. Rev Gastroenterol Peru . (2017) 37:240–5.

PubMed Abstract | Google Scholar

19. Mazahreh, TS, Aleshawi, AJ, Alorjani, MS, Elayyan, R, and Al-Zoubi, NA. Arteriovenous malformations within jejunal diverticulosis: cb ase report and literature review. BMC Surg . (2019) 19:70. doi: 10.1186/s12893-019-0538-0

Keywords: intestinal perforation, jejunal diverticulosis, diverticulitis, segmental resection, surgical treatment

Citation: Chiorescu S, Mocan M, Santa ME, Mihăileanu F and Chiorescu RM (2024) Acute complicated jejunum diverticulitis: a case report with a short literature review. Front. Med . 11:1413254. doi: 10.3389/fmed.2024.1413254

Received: 06 April 2024; Accepted: 23 April 2024; Published: 15 May 2024.

Reviewed by:

Copyright © 2024 Chiorescu, Mocan, Santa, Mihăileanu and Chiorescu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Mihaela Mocan, [email protected]

This article is part of the Research Topic

Diverticulitis - A Neglected Disease Despite its Clinical Burden

Current Physical Therapy for Skin Scars Management: A Scoping Review Protocol

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Background: Scar impairments impose a great economic burden and influence a subject's well-being and quality of life. Despite that, physiotherapy interventions are poorly investigated. Objective of the study: Provide a comprehensive overview of studies addressing physiotherapy and conservative non-invasive interventions for skin scar management, summarizing studies based on scar type, localization, patient's characteristics (e.g., age), safety and tolerance of physical interventions. The realization of an infographic will assist clinicians and patients with scars' management. Moreover, any knowledge gaps will be identified. Methods: The review will be conducted following the Joanna Briggs Institute Manual for Evidence Synthesis. MEDLINE Central, PEDro, Embase, Cochrane Library and Central Register of Controlled Trials (CENTRAL) and CINAHL and grey literature (e.g., Google Scholar) will be searched for studies considering physical therapy interventions in scars management. Every study considering conservative non-invasive physiotherapy interventions for scar management will be included. This review will look at studies carried out in any context. Articles written in English or Italian will be considered. No temporal or publication type restrictions will be placed. Selection and extraction of data will be done by three reviewers independently, any discrepancies will be resolved by a fourth reviewer. The results will be illustrated using descriptive statistics and summarized in an infographic. Ethics and dissemination: No ethics approval will be necessary.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study did not receive any funding.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Data Availability

All data produced in the present study are available upon reasonable request to the authors. All data produced in the present work are contained in the manuscript.

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