place the steps of a literature review in order

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Literature Reviews

Steps in the literature review process.

• What is a literature review?
• Define your research question
• Determine inclusion and exclusion criteria
• Choose databases and search
• Review Results
• Synthesize Results
• Analyze Results
• Librarian Support
• You may need to some exploratory searching of the literature to get a sense of scope, to determine whether you need to narrow or broaden your focus
• Identify databases that provide the most relevant sources, and identify relevant terms (controlled vocabularies) to add to your search strategy
• Finalize your research question
• Think about relevant dates, geographies (and languages), methods, and conflicting points of view
• Conduct searches in the published literature via the identified databases
• Check to see if this topic has been covered in other discipline's databases
• Examine the citations of on-point articles for keywords, authors, and previous research (via references) and cited reference searching.
• Save your search results in a citation management tool (such as Zotero, Mendeley or EndNote)
• De-duplicate your search results
• Make sure that you've found the seminal pieces -- they have been cited many times, and their work is considered foundational 
• Check with your professor or a librarian to make sure your search has been comprehensive
• Evaluate the strengths and weaknesses of individual sources and evaluate for bias, methodologies, and thoroughness
• Group your results in to an organizational structure that will support why your research needs to be done, or that provides the answer to your research question  
• Develop your conclusions
• Are there gaps in the literature?
• Where has significant research taken place, and who has done it?
• Is there consensus or debate on this topic?
• Which methodological approaches work best?
• For example: Background, Current Practices, Critics and Proponents, Where/How this study will fit in 
• Organize your citations and focus on your research question and pertinent studies
• Compile your bibliography

Note: The first four steps are the best points at which to contact a librarian. Your librarian can help you determine the best databases to use for your topic, assess scope, and formulate a search strategy.

Videos Tutorials about Literature Reviews

This 4.5 minute video from Academic Education Materials has a Creative Commons License and a British narrator.

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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.

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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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Conducting a Literature Review

Steps in conducting a literature review.

• Benefits of Conducting a Literature Review
• Summary of the Process
• Additional Resources
• Literature Review Tutorial by American University Library
• The Literature Review: A Few Tips On Conducting It by University of Toronto
• Write a Literature Review by UC Santa Cruz University Library

Conducting a literature review involves using research databases to identify materials that cover or are related in some sense to the research topic. In some cases the research topic may be so original in its scope that no one has done anything exactly like it, so research that is at least similar or related will provide source material for the literature review. The selection of databases will be driven by the subject matter and the scope of the project.

Selecting Databases -- Most academic libraries now provide access to a majority of their databases and their catalog via a so-called discovery tool. A discovery tool makes searching library systems more "Google-like" in that even the simplest of queries can be entered and results retrieved. However, many times the results are also "Google-like" in the sheer quantity of items retrieved. While a discovery tool can be invaluable for quickly finding a multitude of resources on nearly any topic, there are a number of considerations a researcher should keep in mind when using a discovery tool, especially for the researcher who is attempting a comprehensive literature review.

No discovery tool works with every database subscribed to by a library. Some libraries might subscribe to two or three hundred different research databases covering a large number of subject areas. Competing discovery systems might negotiate agreements with different database vendors in order to provide access to a large range of materials. There will be other vendors with whom agreements are not forthcoming, therefore their materials are not included in the discovery tool results. While this might be of only minor concern for a researcher looking to do a fairly limited research project, the researcher looking to do a comprehensive review of the literature in preparation for writing a master's thesis or a doctoral dissertation will run the risk of missing some materials by limiting the search just to a particular library's discovery system. If only one system covered everything that a researcher could possibly need, libraries would have no need to subscribe to hundreds of different databases. The reality is that no one tool does it all. Not even Google Scholar.

Book collections might be excluded from results delivered by a discovery tool. While many libraries are making results from their own catalogs available via their discovery tools, they might not cover books that are discoverable from other library collections, thus making a search of book collections incomplete. Most libraries subscribe to an international database of library catalogs known as WorldCat. This database will provide comprehensive coverage of books, media, and other physical library materials available in libraries worldwide.

Features available in a particular database might not be available in a discovery tool. Keep in mind that a discovery tool is a search system that enables searching across content from numerous individual databases. An individual database might have search features that cannot be provided through a discovery tool, since the discovery tool is designed to accommodate a large number of systems with a single search. For example, the nursing database  CINAHL  includes the ability to limit a search to specific practice areas, to limit to evidence-based practice, to limit to gender, and to search using medical subject headings, among other things, all specialized facets that are not available in a discovery tool. To have these advanced capabilities, a researcher would need to go directly to  CINAHL  and search it natively.

Some discovery tools are set, by default, to limit search results to those items directly available through a particular library's collections. While many researchers will be most concerned with what is immediately available to them at their own library, a researcher concerned with finding everything that has been done on a particular topic will need to go beyond what's available at his or her home library and include materials that are available elsewhere. Master's and doctoral candidates should take care to notice if their library's discovery tool automatically limits to available materials and broaden the scope to include ALL materials, not just those available.

With the foregoing in mind, a researcher might start a search by using the library's discovery tool and then follow up by reviewing which databases have been included in the search and, more importantly, which databases have not been included. Most libraries will facilitate locating its individual databases through a subject arrangement of some kind. Once those databases that are not discoverable have been identified, the researcher would do well to search them individually to find out if other materials can be identified outside of the discovery tool. One additional tool that a doctoral researcher should of necessity include in a search is ISI's  Web of Knowledge . The two major systems searchable within ISI's  Web  are the  Social Sciences Citation Index  and the  Science Citation Index . The purpose of these two systems is to enable a researcher to determine what research has been cited over the years by any number of researchers and how many times it has been cited.

Formulating an Effective Search Strategy -- Key to performing an effective literature review is selecting search terms that will effectively identify materials that are relevant to the research topic. An initial strategy for selecting search terminology might be to list all possible relevant terms and their synonyms in order to have a working vocabulary for use in the research databases. While an individual subject database will likely use a "controlled vocabulary" to index articles and other materials that are included in the database, the same vocabulary might not be as effective in a database that focuses on a different subject area. For example, terminology that is used frequently in psychological literature might not be as effective in searching a human resources management database. Brainstorming the topic before launching into a search will help a researcher arrive at a good working vocabulary to use when probing the databases for relevant literature.

As materials are identified with the initial search, the researcher will want to keep track of other terminology that could be of use in performing additional searches. Sometimes the most effective search terminology can be found by reading the abstracts of relevant materials located through a library's research databases. For example, an initial search on the concept of "mainstreaming" might lead the researcher to articles that discuss mainstreaming but which also look into the concept of "inclusion" in education. While the terms mainstreaming and inclusion are sometimes used synonymously, they really embody two different approaches to working with students having special needs. Abstracts of articles located in the initial search on mainstreaming will uncover related concepts such as inclusion and help a researcher develop a better, more effective vocabulary for fleshing out the literature review.

In addition to searching using key concepts aligned with the research topic, a researcher likely also will want to search for additional materials produced by key authors who are identified in the initial searches. As a researcher reviews items retrieved in the initial stages of the survey, he or she will begin to notice certain authors coming up over and over in relation to the topic. To make sure that no stone is left unturned, it would be advisable to search the available, relevant library databases for other materials by those key authors, just to make sure something of importance has not been missed. A review of the reference lists for each of the items identified in the search will also help to identify key literature that should be reviewed.

Locating the Materials and Composing the Review -- In many cases the items identified through the library's databases will also be available online through the same or related databases. This, however, is not always the case. When materials are not available online, the researcher should check the library's physical collections (print, media, etc.) to determine if the items are available in the library, itself. For those materials not physically available in the home library, the researcher will use interlibrary loan to procure copies from other libraries or services. While abstracts are extremely useful in identifying the right types of materials, they are no substitute for the actual items, themselves. The thorough researcher will make sure that all the key literature has been retrieved and read thoroughly before proceeding too far with the original research.

The end result of the literature review is a discussion of the central themes in the research and an overview of the significant studies located by the researcher. This discussion serves as the lead section of a paper or article that reports the findings of an original research study and sets the stage for presentation of the original study by providing a review of research that has been conducted prior to the current study. As the researcher conducts his or her own study, other relevant materials might enter into the professional literature. It is the researcher's responsibility to update the literature review with newly released information prior to completing his or her own study.

Updating the Initial Search -- Most research projects will take place over a period of time and are not completed in the short term. Especially in the case of master's and doctoral projects, the research process might take a year or several years to complete. During this time, it will be important for the researcher to periodically review the research that has been going on at the same time as his or her own research. Revisiting the search strategies employed in the initial pass of the ltierature will turn up any new studies that might have come to light since the initial search. Fortunately, most research databases and discovery systems provide researchers with the means for automatically notifying them when new materials matching the search strategy have entered the system. This requires that a researcher sign up for a personal "account" with the database in order to save his or her searches and set up "alerts" when new materials come online. Setting up an account does not involve charges to the researcher; this is all a part of the cost borne by the home library in providing access to the databases.

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Writing a Literature Review

• What is a Literature Review?
• Step 1: Choosing a Topic
• Step 2: Finding Information
• Step 3: Evaluating Content
• Step 4: Taking Notes
• Step 5: Synthesizing Content
• Step 6: Writing the Review
• Step 7: Citing Your Sources
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Steps To Write a Literature Review

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How to Write a Literature Review

Who is my subject librarian.

• Literature Reviews: A Recap
• Reading Journal Articles
• Does it Describe a Literature Review?
• 1. Identify the Question
• 2. Review Discipline Styles
• Searching Article Databases
• Finding Full-Text of an Article
• Citation Chaining
• When to Stop Searching
• 4. Manage Your References
• 5. Critically Analyze and Evaluate
• 6. Synthesize
• 7. Write a Literature Review

This guide has a Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA) License.

This license lets others remix, tweak, and build upon your work non-commercially, as long as they credit you and license their new creations under the identical terms.

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This guide is organized around the 7 steps in the graphic to the left to help you understand the process of writing a literature review.

This guide will help you to

• Define a literature review
• Recognize that different fields of study have their own way to perform and write literature reviews
• Prepare to search the literature
• Read critically -- analyze and synthesize
• Prepare to write a literature review

At the end of the tutorial, you will find a quiz that you can submit through Canvas for course credit. 

Graphic from Literature Review (2009) by Machi  and McEvoy.

Text description of "Literature Review Process" for web accessibility

If you have questions related to a field or discipline, consider reaching out to a Subject Librarian by email, phone, or by scheduling an appointment for a free consultation:

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How to write a literature review in 6 steps

What is a literature review?

How to write a literature review, 1. determine the purpose of your literature review, 2. do an extensive search, 3. evaluate and select literature, 4. analyze the literature, 5. plan the structure of your literature review, 6. write your literature review, other resources to help you write a successful literature review, frequently asked questions about writing a literature review, related articles.

A literature review is an assessment of the sources in a chosen topic of research.

A good literature review does not just summarize sources. It analyzes the state of the field on a given topic and creates a scholarly foundation for you to make your own intervention. It demonstrates to your readers how your research fits within a larger field of study.

In a thesis, a literature review is part of the introduction, but it can also be a separate section. In research papers, a literature review may have its own section or it may be integrated into the introduction, depending on the field.

➡️ Our guide on what is a literature review covers additional basics about literature reviews.

• Identify the main purpose of the literature review.
• Do extensive research.
• Evaluate and select relevant sources.
• Analyze the sources.
• Plan a structure.
• Write the review.

In this section, we review each step of the process of creating a literature review.

In the first step, make sure you know specifically what the assignment is and what form your literature review should take. Read your assignment carefully and seek clarification from your professor or instructor if needed. You should be able to answer the following questions:

• How many sources do I need to include?
• What types of sources should I review?
• Should I evaluate the sources?
• Should I summarize, synthesize or critique sources?
• Do I need to provide any definitions or background information?

In addition to that, be aware that the narrower your topic, the easier it will be to limit the number of sources you need to read in order to get a good overview of the topic.

Now you need to find out what has been written on the topic and search for literature related to your research topic. Make sure to select appropriate source material, which means using academic or scholarly sources , including books, reports, journal articles , government documents and web resources.

➡️ If you’re unsure about how to tell if a source is scholarly, take a look at our guide on how to identify a scholarly source .

Come up with a list of relevant keywords and then start your search with your institution's library catalog, and extend it to other useful databases and academic search engines like:

• Google Scholar
• Science.gov

➡️ Our guide on how to collect data for your thesis might be helpful at this stage of your research as well as the top list of academic search engines .

Once you find a useful article, check out the reference list. It should provide you with even more relevant sources. Also, keep a note of the:

• authors' names
• page numbers

Keeping track of the bibliographic information for each source will save you time when you’re ready to create citations. You could also use a reference manager like Paperpile to automatically save, manage, and cite your references.

Read the literature. You will most likely not be able to read absolutely everything that is out there on the topic. Therefore, read the abstract first to determine whether the rest of the source is worth your time. If the source is relevant for your topic:

• Read it critically.
• Look for the main arguments.
• Take notes as you read.
• Organize your notes using a table, mind map, or other technique.

Now you are ready to analyze the literature you have gathered. While your are working on your analysis, you should ask the following questions:

• What are the key terms, concepts and problems addressed by the author?
• How is this source relevant for my specific topic?
• How is the article structured? What are the major trends and findings?
• What are the conclusions of the study?
• How are the results presented? Is the source credible?
• When comparing different sources, how do they relate to each other? What are the similarities, what are the differences?
• Does the study help me understand the topic better?
• Are there any gaps in the research that need to be filled? How can I further my research as a result of the review?

Tip: Decide on the structure of your literature review before you start writing.

There are various ways to organize your literature review:

• Chronological method : Writing in the chronological method means you are presenting the materials according to when they were published. Follow this approach only if a clear path of research can be identified.
• Thematic review : A thematic review of literature is organized around a topic or issue, rather than the progression of time.
• Publication-based : You can order your sources by publication, if the way you present the order of your sources demonstrates a more important trend. This is the case when a progression revealed from study to study and the practices of researchers have changed and adapted due to the new revelations.
• Methodological approach : A methodological approach focuses on the methods used by the researcher. If you have used sources from different disciplines that use a variety of research methods, you might want to compare the results in light of the different methods and discuss how the topic has been approached from different sides.

Regardless of the structure you chose, a review should always include the following three sections:

• An introduction, which should give the reader an outline of why you are writing the review and explain the relevance of the topic.
• A body, which divides your literature review into different sections. Write in well-structured paragraphs, use transitions and topic sentences and critically analyze each source for how it contributes to the themes you are researching.
• A conclusion , which summarizes the key findings, the main agreements and disagreements in the literature, your overall perspective, and any gaps or areas for further research.

➡️ If your literature review is part of a longer paper, visit our guide on what is a research paper for additional tips.

➡️ UNC writing center: Literature reviews

➡️ How to write a literature review in 3 steps

➡️ How to write a literature review in 30 minutes or less

The goal of a literature review is to asses the state of the field on a given topic in preparation for making an intervention.

A literature review should have its own independent section. You should indicate clearly in the table of contents where it can be found, and address this section as “Literature Review.”

There is no set amount of words for a literature review; the length depends on the research. If you are working with a large amount of sources, then it will be long. If your paper does not depend entirely on references, then it will be short.

Most research papers include a literature review. By assessing the available sources in your field of research, you will be able to make a more confident argument about the topic.

Literature reviews are most commonly found in theses and dissertations. However, you find them in research papers as well.

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Steps in doing a literature review

The steps below look sequential. However, doing a literature review is often an iterative process. That is, you may “circle back" to redo or modify earlier steps. You may also be working on a number of steps at the same time. 

General steps

State your research topic or question. Ask yourself: What is my central question or issue that the literature can help define? What is already known about the topic?

Clarify the purpose of your review. For example, is it to provide background information for a research paper? Is it for a “pro and con" discussion? Is it to provide a synthesis or summary of the "state of the discipline?" Is it to demonstrate that you are familiar with previous work that has been done in your discipline? You may have several purposes.

Develop a starting search plan. Ask yourself: Where will I find information? (Library databases? Google Scholar? Special digital or physical collections specific to your discipline?) What is the scope of the search? How broadly or narrowly should I search? (Hint: Check out Boston College Libraries' excellent guide on literature review scope .)

Consider using a search log to help you search more effectively. This one was created by the University of Leeds.

Do your search and choose sources that seem to have information on your topic.

Choose the exact information you want to use, discuss, or develop in your review. 

Organize and synthesize the information you've selected. Before beginning to write about the sources, you will probably find it useful to organize the sources -- perhaps thematically, perhaps chronologically. Ask yourself: What connections can be made between the texts? Is there a conflict or debate in the literature? How will reviewing the literature justify the topic I plan to investigate?

IUPUI has created a handy worksheet to help you synthesize multiple authors' research and viewpoints. Florida International University's "synthesis matrix" might also be useful.

Write a draft of the paper or article.

Acknowledgements: This page contains information adapted from Irene Clark's book Writing the Successful Thesis and Dissertation: Entering the Conversation (Upper Saddle River, NJ: Prentice Hall, 2007), pp. 110-111; and from librarian Paul Fehrmann's "Literature Reviews" guide on the Kent State University Libraries website.

Some helpful resources

The following resources, available through the OU Libraries, will give you additional help in developing your literature review.

" How to Write a Literature Review ." By Andrew S. Denney and Richard Tewksbury. Journal of Criminal Justice Education , vol. 24, no. 2 (2013), pp. 218-234.

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Literature Review: Conducting & Writing

• Steps for Conducting a Lit Review

1. Choose a topic. Define your research question.

2. decide on the scope of your review., 3. select the databases you will use to conduct your searches., 4. conduct your searches and find the literature. keep track of your searches, 5. review the literature..

• Finding "The Literature"
• Organizing/Writing
• APA Style This link opens in a new window
• Chicago: Notes Bibliography This link opens in a new window
• MLA Style This link opens in a new window
• Sample Literature Reviews

Disclaimer!!

Conducting a literature review is usually recursive, meaning that somewhere along the way, you'll find yourself repeating steps out-of-order.

That is actually a good sign.  

Reviewing the research should lead to more research questions and those questions will likely lead you to either revise your initial research question or go back and find more literature related to a more specific aspect of your research question.

Your literature review should be guided by a central research question.  Remember, it is not a collection of loosely related studies in a field but instead 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.

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

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

Make a list of the databases you will search.  Remember to include comprehensive databases such as WorldCat and Dissertations & Theses, if you need to.

Where to find databases:

• Find Databases by Subject UWF Databases categorized by discipline
• Find Databases via Research Guides Librarians create research guides for all of the disciplines on campus! Take advantage of their expertise and see what discipline-specific search strategies they recommend!
• Review the abstracts of research studies carefully. This will save you time.
• Write down the searches you conduct in each database so that you may duplicate them if you need to later (or avoid dead-end searches   that you'd forgotten you'd already tried).
• Use the bibliographies and references of research studies you find to locate others.
• Ask your professor or a scholar in the field if you are missing any key works in the field.
• Use RefWorks to keep track of your research citations. See the RefWorks Tutorial if you need help.

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: 

• Again, review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
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A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

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 primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within 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 a number of approaches you could adopt depending upon the type of analysis underpinning your study.

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 [see below].

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 or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena 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 [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon 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. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own 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. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . 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?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to 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.

NOTE : Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

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Research Process Guide

• Step 1 - Identifying and Developing a Topic
• Step 2 - Narrowing Your Topic
• Step 3 - Developing Research Questions
• Step 4 - Conducting a Literature Review
• Step 5 - Choosing a Conceptual or Theoretical Framework
• Step 6 - Determining Research Methodology
• Step 6a - Determining Research Methodology - Quantitative Research Methods
• Step 6b - Determining Research Methodology - Qualitative Design
• Step 7 - Considering Ethical Issues in Research with Human Subjects - Institutional Review Board (IRB)
• Step 8 - Collecting Data
• Step 9 - Analyzing Data
• Step 10 - Interpreting Results
• Step 11 - Writing Up Results

Step 4: Conducting a Literature Review

In order to understand your topic, before you conduct your research, it is extremely important to immerse yourself in the research that has been done on your topic and the topics that might be adjacent to your particular research interest or questions. “a researcher cannot perform significant research without first understanding the literature in the field” (Boote & Beile, 2005, p. 3). Essentially, When writing a thesis or research proposal, the review of the literature would be your Chapter 2 .

Frankly, the literature review is often the first major challenge of the writing process. Sometimes, the task to review and synthesize all of the previous research on and around your topic can feel overwhelming. Although the literature review is foundational to situate your research within the body of literature on your topic, there is almost no literature on the challenges and pitfalls of writing a literature review (Randolph, 2009).

Boote and Beile (2005) reveal through their research on dissertation writing, that although a sophisticated literature review is essential for substantial research, they are often poorly written and lack organizational structure and conceptual relevance. So, the question is, how can you write a literature that is well-organized, comprehensive and situate your research within the literature?

Onweugbuzie et al. (2012) identify 23 core components of an effective literature review in their research and are referred to as the standard checklist for most empirical researchers. The list includes the following:

• What has been researched and what needs to be in the future.
• Identify variables within the literature that are relevant to your study.
• Identify the relationship between theory and practice within the literature.
• Discuss the quality of research with particular emphasis on the exemplary studies.
• Examine the methodologies and research design used throughout the literature, and evaluate the efficacy.
• Pay attention to any contradictions within the literature and
• Make sure to not replicate studies that have already been completed, however, if there are similarities, identify how your study and variables examined are important, different, and relevant.

How to complete a literature review

Fair Warning: The literature review is often time-consuming and can feel like an endless process.  Don’t Give Up! It is the first major hurdle of the research proposal process. Once you have completed the literature review, you will have a good idea of what is significant, relevant and novel about your research. The key is to spend time reading, recording important findings, and organizing the scholarly literature on (and around) your topic.

At this point, it is important to distinguish between scholarly literature and other sources. You need to keep in mind that you are only reviewing scholarly literature, which includes sources and studies that have a clear methodology, empirical evidence, results and conclusions. These studies are PEER-REVIEWED, meaning, contemporaries in the field have reviewed the research methods and findings of the literature, and found them relevant, significant, authentic and valid (Wakefield, 2015).

Where do you begin? Great question.

According to Randolph (2009), the goal of a literature review is to integrate and generalize findings across studies, debate findings within a field, resolve the debate, and discuss the language specific to the field. For a meta-analysis, which is a common strategy for a literature review, the goal is largely to integrate quantitative findings across the research on the topic. For other strategies to complete the literature review, the goals may be to critically analyze previous studies, identify central themes or issues within the existing literature or analyze an argument in the field (Randolph, 2009). In literature reviews for dissertation, the goal is to largely interrogate and analyze the current findings to find weaknesses or contradictions in order to place your study within the context of the current literature and to justify your study’s relevance.  So in essence, the goals of literature review, regardless of the strategy, are not only to deal with the central theme across the literature and to present a thematic analysis of that literature, but also, and perhaps more importantly, it is to focus on whether the body of knowledge is credible, reliable and valid based on the methodological approaches and outcomes of the literature in the field (Wakefield, 2015).

A few initial steps are:

• Develop a list of key words and phrases that relate to your topic and questions (Denney & Tewksbury, 2013).
• Search for relevant sources using useful databases found in Kean University’s Library :
• Kean University’s WorldCat Discovery single-search application
• ERIC (education)
• JSTOR (multidisciplinary)
• Project Muse (humanities and social science)
• Web of Science (citation searching)
• Google Scholar
• Set up an account with a bibliographic citation manager like EndNote Online (access provided by Kean University) or a freely available option such as Zotero. The EndNote Online Guide provides separate on-campus and off-campus account registration instructions. A bibliographic citation manager will not only help you manage and organize your sources, but it will also help you format your references in various citation styles.
• Take advantage of research support options provided by Kean’s librarians, including workshops , appointments with a librarian , and 24/7 Chat .

If you identify a source (article or book) that is not available through Kean University’s library collections, you may submit an Interlibrary Loan request. Book or article records found in the WorldCat Discovery database will feature an Interlibrary Loan request option. However, you may also utilize the Interlibrary Loan form .

You may also use the VALE Reciprocal Borrowing Program , which enables Kean University students and faculty to check out books from libraries at other New Jersey colleges and universities. To participate in this program, a researcher must first obtain a signed "VALE Reciprocal Borrowing Application Form" from the Nancy Thompson Learning Commons before they can borrow at one of the participating libraries .

What are the sources that are appropriate for a literature review? According to Garrard (2009) and others scientific or empirical research refers to the:

         …theoretical and research publications in scientific journals, reference books, government practice, policy statements, and other materials          about the theory, practice, and results of scientific inquiry. These materials and publications are produced by individuals or groups in          universities, foundations, government research laboratories, and other nonprofit or for-profit organizations (p.4). Onwuegbuzie et al. (2010; as cited in Onwuegbuzie et al., 2012) goes further and describes the literature that could be included in a literature review, “research articles,… essays, article reviews, monographs, dissertations, books, Internet websites, video, interview transcripts, encyclopedias, company reports, trade catalogues, government documents, congressional/parliamentary bills…” (p. 7). However, Onwuegbuzie et al. (2012) builds on this definition, by saying that a literature review is largely, “a systematic, explicit, and reproducible method for identifying, evaluating, and synthesizing the existing body of completed and recorded work produced by researchers, scholars and practitioners” (p.3).

So, what does this mean for you, the researcher and author of the literature review? You want to use multiple source types. Additionally, stick to the parameters laid out by Onwuegbuzie et al. (2012)  in that the literature reviewed should be an evaluation and synthesis of the existing work completed by “researchers, scholars and practitioners.” The list of sources should be semi-exhaustive and representative of the field.

Next, you should:

     3. Evaluate and select your sources. Read the abstract first to see if the source is relevant to your topic (Wakefield, 2015; Denney & Tewksbury, 2013; Randolph, 2009).

• Is this source peer-reviewed?
• Is this source presenting empirical evidence, meeting the threshold for scholarly research?
• Is this topic relevant to my research topic/questions?

Organizing your Literature Review:

Outline your literature review- how do you want it organized? You are “synthesizing” the literature as your purpose here. What structure works best for your topic and study? The most common formats are (Randolph, 2009; Onwuegbuzie et al., 2012):

• Historical format - literature is reviewed chronologically.This method is preferred when there is a goal of analyzing the progression of research methods, theories or practices over time.
• Conceptual format - centered arounds the propositions in research rationale or a theoretical- centered review which is organized according to the theories in the literature.
• Methodological format - this involves the discussion of methodology  as in an imperial paper including an introduction, method, results and discussion. This approach is most commonly used in meta- analytical reports.

Let’s talk about synthesis.

A literature review is not only a review of the empirical research, but it is also evaluation and synthesis of the research. Boote and Beile (2005) have created a five- category list for evaluating a literature review. The categories are coverage, synthesis, methodology, significance, and rhetoric .

• You need to create a justified criteria for including and excluding studies from your review
• You need to discuss what has been done in the field and what still needs to be done.
• Place the topic or problem within the greater context of scholarly literature.
• Place the topic or problem within the historical context.
• Discuss the subject vocabulary.
• Articulate the important variables and phenomena that are relevant to the topic.
• Synthesize and discuss a new perspective on the literature.
• Identify the main methods and research techniques that have been used in the field as well as their advantages/disadvantages.
• Relate ideas and theories to research methodologies.
• Rationalize the practical significance of the research problem.
• Rationalize the scholarly significance of the research problem.
• Write in coherent language and be sure the organization/ structure of the review makes sense.

Synthesis is difficult - you need to articulate what this literature means for your research and/or how does the literature inform the purpose, impact, methodology of your study? Rather than summarizing, the idea behind synthesis is taking the information you have discussed and drawing your own conclusions, making connections between the literature and your study.

Boote, D. N., & Beile, P. (2005). Scholars before researchers: On the centrality of the dissertation literature review in research preparation. Educational Researcher, 34 (6), 3-15. https://www.jstor.org/stable/3699805

Denney, A. S., & Tewksbury, R. (2013). How to write a literature review. Journal of Criminal Justice Education, 24 (2), 218-234. https://doi-org.kean.idm.oclc.org/10.1080/10511253.2012.730617

Garrard, J. (2009). Health sciences literature review made easy: The matrix method.  Jones and Bartlett.

Onwuegbuzie, A. J., Leech, N. L., & Collins, K. M. (2012). Qualitative analysis techniques for the review of the literature. Qualitative Report, 17( 28), 1-28.

Randolph, J. (2009). A guide to writing the dissertation literature review. Practical Assessment, Research, and Evaluation, 14 (1), 13.

Wakefield, A. (2015). Synthesising the literature as part of a literature review. Nursing Standard, 29 (29), 44-51. https://doi.org/10.7748/ns.29.29.44.e8957

• Last Updated: Jun 29, 2023 1:35 PM
• URL: https://libguides.kean.edu/ResearchProcessGuide

Doing a literature review: an 8-step process

Overview of my presentation in the Middlesex University PhD coursework - with embedded videos of the 8 steps

Anne-Wil Harzing - Mon 1 Jan 2024 09:31 (updated Tue 2 Jan 2024 08:14)

Copyright 2024 Anne-Wil Harzing. All rights reserved. First version, 2 January 2024

Step 1: Information management strategies

Step 2: situating the literature review, step 3: sources of literature, step 4: keeping current, step 5: how much is enough, step 6: different types of papers.

• Step 7a: Seven criteria to evaluate coverage
• Step 7b: Twelve guidelines to evaluate references

Step 8: The literature review in your thesis

Your challenge is very different from what mine was during my PhD. I completed my PhD before the internet was available. So my challenge was to get access to information and find the time and money to do so. Oftentimes, this involved traveling to various libraries across the country.

Your challenge is to manage the wealth of information you have easy access to, but not to waste too much time on completely irrelevant information. This step provides you with some tips on how to approach this.

In this step, you learn why a literature review is important in no less than six of the nine stages of the research process. Before watching it, try and list the stages where you think it might be important.

In this step, we review the various sources you can use for literature reviews: books, journal articles, government and industry resources, working papers, and conference papers. I show you the relative merits of each of these.

Here I share my top tips on how to keep up to date with new publications. You can find more information about this here: How to keep up-to-date with the literature, but avoid information overload? .

Note that my tips focus on the "old-fashioned" tried-and-tested approaches. This process has now been facilitated by many dedicated tools, often using artificial intelligence. I can't say I like working with these as they do not facilitate the deep engagement that I think is needed for academic research, but they might well work for you.

The next step is deciding when to stop. How do you know you have "enough"? When can you stop? Well obviously, you never completely stop reviewing the literature, as it is important in so many stages of the review process (see step 2).

But in deciding when you can start writing up, I do suggest the use of a relevance tree in this video. I also show how you can use tables to effectively summarise literature. Further tips on how many references to use in writing up can be found here: How many references is enough?

In this step, I review three types of papers to look out for to maximise the effectiveness of your literature review: review papers, star papers, model papers.

Step 7a: 7 criteria to evaluate coverage

How do you evaluate whether all the literature you have collected is actually useful for your thesis or article?

In this step I go through seven criteria you can use to evaluate coverage of the collected literature: relevance, currency, reliability, audience, accuracy, scope, and objectivity.

Step 7b: 12 guidelines to evaluate references

If you are going to use the literature to reference arguments in your thesis, this step covers twelve guidelines you can use to evaluate other academics' referencing practices as well as to make sure you do this right. They are also described in detail in this blogpost: Are referencing errors undermining our scholarship and credibility?

My twelve guidelines are based on research in my own PhD, written up as a paper that turned out to be very hard to publish. If you are interested, you can read the full story here: How to publish an unusual paper? Referencing errors, scholarship & credibility .

This last step reveals what criteria are used to evaluate the literature review in your own thesis: synthesis, critical appraisal, and application to the research question. I also explain what your literature should not look like and why a good literature review helps you to get papers published.

Related blogposts

• Want to publish a literature review? Think of it as an empirical paper
• Do you really want to publish your literature review? Advice for PhD students
• How to keep up-to-date with the literature, but avoid information overload?
• Is a literature review publication a low-cost project?
• Using Publish or Perish to do a literature review
• How to conduct a longitudinal literature review?
• New: Publish or Perish now also exports abstracts
• A framework for your literature review article: where to find one?

Find the resources on my website useful?

I cover all the expenses of operating my website privately. If you enjoyed this post and want to support me in maintaining my website, consider buying a copy of one of my books (see below) or supporting the Publish or Perish software .

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Literature Reviews

• "How To" Books
• Examples of Literature Reviews
• Collecting Resources for a Literature Review
• Organizing the Literature Review
• Writing the Literature Review
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• Evaluating Websites

Organization

Organization of your Literature Review

What is the most effective way of presenting the information? What are the most important topics, subtopics, etc., that your review needs to include? What order should you present them?

Just like most academic papers, literature reviews must contain at least three basic elements: an introduction or background information section; the body of the review containing the discussion of sources; and, finally, a conclusion and/or recommendations section to end the paper.

Introduction: Gives a quick idea of the topic of the literature review, such as the central theme or organizational pattern.

Body: Contains your discussion of sources and is organized either chronologically, thematically, or methodologically (see below for more information on each).

Conclusions/Recommendations: Discuss what you have drawn from reviewing the literature so far. Where might the discussion proceed?

Once you have the basic categories in place, then you must consider how you will present the sources themselves within the body of your paper. Create an organizational method to focus this section even further.

To help you come up with an overall organizational framework for your review, consider the following scenario and then three typical ways of organizing the sources into a review:

You've decided to focus your literature review on materials dealing with sperm whales. This is because you've just finished reading Moby Dick, and you wonder if that whale's portrayal is really real. You start with some articles about the physiology of sperm whales in biology journals written in the 1980's. But these articles refer to some British biological studies performed on whales in the early 18th century. So you check those out. Then you look up a book written in 1968 with information on how sperm whales have been portrayed in other forms of art, such as in Alaskan poetry, in French painting, or on whale bone, as the whale hunters in the late 19th century used to do. This makes you wonder about American whaling methods during the time portrayed in Moby Dick, so you find some academic articles published in the last five years on how accurately Herman Melville portrayed the whaling scene in his novel.

Chronological

If your review follows the chronological method, you could write about the materials above according to when they were published. For instance, first you would talk about the British biological studies of the 18th century, then about Moby Dick, published in 1851, then the book on sperm whales in other art (1968), and finally the biology articles (1980s) and the recent articles on American whaling of the 19th century. But there is relatively no continuity among subjects here. And notice that even though the sources on sperm whales in other art and on American whaling are written recently, they are about other subjects/objects that were created much earlier. Thus, the review loses its chronological focus.

By publication

Order your sources chronologically by publication if the order demonstrates a more important trend. For instance, you could order a review of literature on biological studies of sperm whales if the progression revealed a change in dissection practices of the researchers who wrote and/or conducted the studies.

Another way to organize sources chronologically is to examine the sources under a trend, such as the history of whaling. Then your review would have subsections according to eras within this period. For instance, the review might examine whaling from pre-1600-1699, 1700-1799, and 1800-1899. Using this method, you would combine the recent studies on American whaling in the 19th century with Moby Dick itself in the 1800-1899 category, even though the authors wrote a century apart.

Thematic reviews of literature are organized around a topic or issue, rather than the progression of time. However, progression of time may still be an important factor in a thematic review. For instance, the sperm whale review could focus on the development of the harpoon for whale hunting. While the study focuses on one topic, harpoon technology, it will still be organized chronologically. The only difference here between a "chronological" and a "thematic" approach is what is emphasized the most: the development of the harpoon or the harpoon technology.

More authentic thematic reviews tend to break away from chronological order. For instance, a thematic review of material on sperm whales might examine how they are portrayed as "evil" in cultural documents. The subsections might include how they are personified, how their proportions are exaggerated, and their behaviors misunderstood. A review organized in this manner would shift between time periods within each section according to the point made.

Methodological

A methodological approach differs from the two above in that the focusing factor usually does not have to do with the content of the material. Instead, it focuses on the "methods" of the researcher or writer. For the sperm whale project, one methodological approach would be to look at cultural differences between the portrayal of whales in American, British, and French art work. Or the review might focus on the economic impact of whaling on a community. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Once you've decided on the organizational method for the body of the review, the sections you need to include in the paper should be easy to figure out. They should arise out of your organizational strategy. In other words, a chronological review would have subsections for each vital time period. A thematic review would have subtopics based upon factors that relate to the theme or issue.

Sometimes, though, you might need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. Put in only what is necessary. Here are a few other sections you might want to consider:

Current Situation: Information necessary to understand the topic or focus of the literature review.

History: The chronological progression of the field, the literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.

Methods and/or Standards: The criteria you used to select the sources in your literature review or the way in which you present your information. For instance, you might explain that your review includes only peer-reviewed articles and journals.

Questions for Further Research: What questions about the field has the review sparked? How will you further your research as a result of the review?

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Systematic Review

• Library Help
• What is a Systematic Review (SR)?

Steps of a Systematic Review

• Framing a Research Question
• Developing a Search Strategy
• Searching the Literature
• Managing the Process
• Meta-analysis
• Publishing your Systematic Review

Forms and templates

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• PICO Template
• Inclusion/Exclusion Criteria
• Database Search Log
• Review Matrix
• Cochrane Tool for Assessing Risk of Bias in Included Studies

   • PRISMA Flow Diagram  - Record the numbers of retrieved references and included/excluded studies. You can use the Create Flow Diagram tool to automate the process.

   •  PRISMA Checklist - Checklist of items to include when reporting a systematic review or meta-analysis

PRISMA 2020 and PRISMA-S: Common Questions on Tracking Records and the Flow Diagram

• PROSPERO Template
• Manuscript Template
• Steps of SR (text)
• Steps of SR (visual)
• Steps of SR (PIECES)

Adapted from  A Guide to Conducting Systematic Reviews: Steps in a Systematic Review by Cornell University Library

Source: Cochrane Consumers and Communications  (infographics are free to use and licensed under Creative Commons )

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• v.96(3); 2003 Mar

Five steps to conducting a systematic review

Regina kunz.

1 German Cochrane Centre, Freiburg and Department of Nephrology, Charité, Berlin, Germany

Jos Kleijnen

2 Centre for Reviews and Dissemination, York, UK

3 German Cochrane Centre, Freiburg, Germany

Systematic reviews and meta-analyses are a key element of evidence-based healthcare, yet they remain in some ways mysterious. Why did the authors select certain studies and reject others? What did they do to pool results? How did a bunch of insignificant findings suddenly become significant? This paper, along with a book 1 that goes into more detail, demystifies these and other related intrigues.

A review earns the adjective systematic if it is based on a clearly formulated question, identifies relevant studies, appraises their quality and summarizes the evidence by use of explicit methodology. It is the explicit and systematic approach that distinguishes systematic reviews from traditional reviews and commentaries. Whenever we use the term review in this paper it will mean a systematic review . Reviews should never be done in any other way.

In this paper we provide a step-by-step explanation—there are just five steps—of the methods behind reviewing, and the quality elements inherent in each step (Box 1). For purposes of illustration we use a published review concerning the safety of public water fluoridation, but we must emphasize that our subject is review methodology, not fluoridation.

EXAMPLE: SAFETY OF PUBLIC WATER FLUORIDATION

You are a public health professional in a locality that has public water fluoridation. For many years, your colleagues and you have believed that it improves dental health. Recently there has been pressure from various interest groups to consider the safety of this public health intervention because they fear that it is causing cancer. Public health decisions have been based on professional judgment and practical feasibility without explicit consideration of the scientific evidence. (This was yesterday; today the evidence is available in a York review 2 , 3 , identifiable on MEDLINE through the freely accessible PubMed clinical queries interface [ http://www.ncbi.nlm.nib.gov/entrez/query/static/clinical.html ], under ‘systematic reviews’.)

STEP 1: FRAMING THE QUESTION

The research question may initially be stated as a query in free form but reviewers prefer to pose it in a structured and explicit way. The relations between various components of the question and the structure of the research design are shown in Figure 1 . This paper focuses only on the question of safety related to the outcomes described below.

Structured questions for systematic reviews and relations between question components in a comparative study

Box 1 The steps in a systematic review

The problems to be addressed by the review should be specified in the form of clear, unambiguous and structured questions before beginning the review work. Once the review questions have been set, modifications to the protocol should be allowed only if alternative ways of defining the populations, interventions, outcomes or study designs become apparent

The search for studies should be extensive. Multiple resources (both computerized and printed) should be searched without language restrictions. The study selection criteria should flow directly from the review questions and be specified a priori . Reasons for inclusion and exclusion should be recorded

Study quality assessment is relevant to every step of a review. Question formulation (Step 1) and study selection criteria (Step 2) should describe the minimum acceptable level of design. Selected studies should be subjected to a more refined quality assessment by use of general critical appraisal guides and design-based quality checklists (Step 3). These detailed quality assessments will be used for exploring heterogeneity and informing decisions regarding suitability of meta-analysis (Step 4). In addition they help in assessing the strength of inferences and making recommendations for future research (Step 5)

Data synthesis consists of tabulation of study characteristics, quality and effects as well as use of statistical methods for exploring differences between studies and combining their effects (meta-analysis). Exploration of heterogeneity and its sources should be planned in advance (Step 3). If an overall meta-analysis cannot be done, subgroup meta-analysis may be feasible

The issues highlighted in each of the four steps above should be met. The risk of publication bias and related biases should be explored. Exploration for heterogeneity should help determine whether the overall summary can be trusted, and, if not, the effects observed in high-quality studies should be used for generating inferences. Any recommendations should be graded by reference to the strengths and weaknesses of the evidence

Free-form question

Is it safe to provide population-wide drinking water fluoridation to prevent caries?

Structured question

• The populations —Populations receiving drinking water sourced through a public water supply
• The interventions or exposures —Fluoridation of drinking water (natural or artificial) compared with non-fluoridated water
• The outcomes —Cancer is the main outcome of interest for the debate in your health authority
• The study designs —Comparative studies of any design examining the harmful outcomes in at least two population groups, one with fluoridated drinking water and the other without. Harmful outcomes can be rare and they may develop over a long time. There are considerable difficulties in designing and conducting safety studies to capture these outcomes, since a large number of people need to be observed over a long period. These circumstances demand observational, not randomized studies. With this background, systematic reviews on safety have to include evidence from studies with a range of designs.

STEP 2: IDENTIFYING RELEVANT PUBLICATIONS

To capture as many relevant citations as possible, a wide range of medical, environmental and scientific databases were searched to identify primary studies of the effects of water fluoridation. The electronic searches were supplemented by hand searching of Index Medicus and Excerpta Medica back to 1945. Furthermore, various internet engines were searched for web pages that might provide references. This effort resulted in 3246 citations from which relevant studies were selected for the review. Their potential relevance was examined, and 2511 citations were excluded as irrelevant. The full papers of the remaining 735 citations were assessed to select those primary studies in man that directly related to fluoride in drinking water supplies, comparing at least two groups. These criteria excluded 481 studies and left 254 in the review. They came from thirty countries, published in fourteen languages between 1939 and 2000. Of these studies 175 were relevant to the question of safety, of which 26 used cancer as an outcome.

STEP 3: ASSESSING STUDY QUALITY

Design threshold for study selection.

Adequate study design as a marker of quality, is listed as an inclusion criterion in Box 1. This approach is most applicable when the main source of evidence is randomized studies. However, randomized studies are almost impossible to conduct at community level for a public health intervention such as water fluoridation. Thus, systematic reviews assessing the safety of such interventions have to include evidence from a broader range of study designs. Consideration of the type and amount of research likely to be available led to inclusion of comparative studies of any design. In this way, selected studies provided information about the harmful effects of exposure to fluoridated water compared with non-exposure.

Quality assessment of safety studies

After studies of an acceptable design have been selected, their in-depth assessment for the risk of various biases allows us to gauge the quality of the evidence in a more refined way. Biases either exaggerate or underestimate the ‘true’ effect of an exposure. The objective of the included studies was to compare groups exposed to fluoridated drinking water and those without such exposure for rates of undesirable outcomes, without bias. Safety studies should ascertain exposures and outcomes in such a way that the risk of misclassification is minimized. The exposure is likely to be more accurately ascertained if the study was prospective rather than retrospective and if it was started soon after water fluoridation rather than later. The outcomes of those developing cancer (and remaining free of cancer) are likely to be more accurately ascertained if the follow-up was long and if the assessment was blind to exposure status.

When examining how the effect of exposure on outcome was established, reviewers assessed whether the comparison groups were similar in all respects other than their exposure to fluoridated water. This is because the other differences may be related to the outcomes of interest independent of the drinking-water fluoridation, and this would bias the comparison. For example, if the people exposed to fluoridated water had other risk factors that made them more prone to have cancer, the apparent association between exposure and outcome might be explained by the more frequent occurrence of these factors among the exposed group. The technical word for such defects is confounding. In a randomized study, confounding factors are expected to be roughly equally distributed between groups. In observational studies their distribution may be unequal. Primary researchers can statistically adjust for these differences, when estimating the effect of exposure on outcomes, by use of multivariable modelling.

Put simply, use of a prospective design, robust ascertainment of exposure and outcomes, and control for confounding are the generic issues one would look for in quality assessment of studies on safety. Consequently, studies may range from satisfactorily meeting quality criteria, to having some deficiencies, to not meeting the criteria at all, and they can be assigned to one of three prespecified quality categories as shown in Table 1 . A quality hierarchy can then be developed, based on the degree to which studies comply with the criteria. None of the studies on cancer were in the high-quality category, but this was because randomized studies were non-existent and control for confounding was not always ideal in the observational studies. There were 8 studies of moderate quality and 18 of low quality.

Description of quality assessment of studies on safety of public water fluoridation

STEP 4: SUMMARIZING THE EVIDENCE

To summarize the evidence from studies of variable design and quality is not easy. The original review 3 provides details of how the differences between study results were investigated and how they were summarized (with or without meta-analysis). This paper restricts itself to summarizing the findings narratively. The association between exposure to fluoridated water and cancer in general was examined in 26 studies. Of these, 10 examined all-cause cancer incidence or mortality, in 22 analyses. Of these, 11 analyses found a negative association (fewer cancers due to exposure), 9 found a positive one and 2 found no association. Only 2 studies reported statistically significant differences. Thus no clear association between water fluoridation and increased cancer incidence or mortality was apparent. Bone/joint and thyroid cancers were of particular concern because of fluoride uptake by these organs. Neither the 6 studies of osteosarcoma nor the 2 studies of thyroid cancer and water fluoridation revealed significant differences. Overall no association was detected between water fluoridation and mortality from any cancer. These findings were also borne out in the moderate-quality subgroup of studies.

STEP 5: INTERPRETING THE FINDINGS

In the fluoridation example, the focus was on the safety of a community-based public health intervention. The generally low quality of available studies means that the results must be interpreted with caution. However, the elaborate efforts in searching an unusually large number of databases provide some safeguard against missing relevant studies. Thus the evidence summarized in this review is likely to be as good as it will get in the foreseeable future. Cancer was the harmful outcome of most interest in this instance. No association was found between exposure to fluoridated water and specific cancers or all cancers. The interpretation of the results may be generally limited because of the low quality of studies, but the findings for the cancer outcomes are supported by the moderate-quality studies.

After having spent some time reading and understanding the review, you are impressed by the sheer amount of published work relevant to the question of safety. However, you are somewhat disappointed by the poor quality of the primary studies. Of course, examination of safety only makes sense in a context where the intervention has some beneficial effect. Benefit and harm have to be compared to provide the basis for decision making. On the issue of the beneficial effect of public water fluoridation, the review 3 reassures you that the health authority was correct in judging that fluoridation of drinking water prevents caries. From the review you also discovered that dental fluorosis (mottled teeth) was related to concentration of fluoride. When the interest groups raise the issue of safety again, you will be able to declare that there is no evidence to link cancer with drinking-water fluoridation; however, you will have to come clean about the risk of dental fluorosis, which appears to be dose dependent, and you may want to measure the fluoride concentration in the water supply and share this information with the interest groups.

The ability to quantify the safety concerns of your population through a review, albeit from studies of moderate to low quality, allows your health authority, the politicians and the public to consider the balance between beneficial and harmful effects of water fluoridation. Those who see the prevention of caries as of primary importance will favour fluoridation. Others, worried about the disfigurement of mottled teeth, may prefer other means of fluoride administration or even occasional treatment for dental caries. Whatever the opinions on this matter, you are able to reassure all parties that there is no evidence that fluoridation of drinking water increases the risk of cancer.

With increasing focus on generating guidance and recommendations for practice through systematic reviews, healthcare professionals need to understand the principles of preparing such reviews. Here we have provided a brief step-by-step explanation of the principles. Our book 1 describes them in detail.