systematic literature review vs literature review

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Systematic Literature Review or Literature Review?

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As a researcher, you may be required to conduct a literature review. But what kind of review do you need to complete? Is it a systematic literature review or a standard literature review? In this article, we’ll outline the purpose of a systematic literature review, the difference between literature review and systematic review, and other important aspects of systematic literature reviews.

What is a Systematic Literature Review?

The purpose of systematic literature reviews is simple. Essentially, it is to provide a high-level of a particular research question. This question, in and of itself, is highly focused to match the review of the literature related to the topic at hand. For example, a focused question related to medical or clinical outcomes.

The components of a systematic literature review are quite different from the standard literature review research theses that most of us are used to (more on this below). And because of the specificity of the research question, typically a systematic literature review involves more than one primary author. There’s more work related to a systematic literature review, so it makes sense to divide the work among two or three (or even more) researchers.

Your systematic literature review will follow very clear and defined protocols that are decided on prior to any review. This involves extensive planning, and a deliberately designed search strategy that is in tune with the specific research question. Every aspect of a systematic literature review, including the research protocols, which databases are used, and dates of each search, must be transparent so that other researchers can be assured that the systematic literature review is comprehensive and focused.

Most systematic literature reviews originated in the world of medicine science. Now, they also include any evidence-based research questions. In addition to the focus and transparency of these types of reviews, additional aspects of a quality systematic literature review includes:

• Clear and concise review and summary
• Comprehensive coverage of the topic
• Accessibility and equality of the research reviewed

Systematic Review vs Literature Review

The difference between literature review and systematic review comes back to the initial research question. Whereas the systematic review is very specific and focused, the standard literature review is much more general. The components of a literature review, for example, are similar to any other research paper. That is, it includes an introduction, description of the methods used, a discussion and conclusion, as well as a reference list or bibliography.

A systematic review, however, includes entirely different components that reflect the specificity of its research question, and the requirement for transparency and inclusion. For instance, the systematic review will include:

• Eligibility criteria for included research
• A description of the systematic research search strategy
• An assessment of the validity of reviewed research
• Interpretations of the results of research included in the review

As you can see, contrary to the general overview or summary of a topic, the systematic literature review includes much more detail and work to compile than a standard literature review. Indeed, it can take years to conduct and write a systematic literature review. But the information that practitioners and other researchers can glean from a systematic literature review is, by its very nature, exceptionally valuable.

This is not to diminish the value of the standard literature review. The importance of literature reviews in research writing is discussed in this article . It’s just that the two types of research reviews answer different questions, and, therefore, have different purposes and roles in the world of research and evidence-based writing.

Systematic Literature Review vs Meta Analysis

It would be understandable to think that a systematic literature review is similar to a meta analysis. But, whereas a systematic review can include several research studies to answer a specific question, typically a meta analysis includes a comparison of different studies to suss out any inconsistencies or discrepancies. For more about this topic, check out Systematic Review VS Meta-Analysis article.

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Know the Difference! Systematic Review vs. Literature Review

It is common to confuse systematic and literature reviews as both are used to provide a summary of the existent literature or research on a specific topic.  Even with this common ground, both types vary significantly.  Please review the following chart (and its corresponding poster linked below) for the detailed explanation of each as well as the differences between each type of review.

• What's in a name? The difference between a Systematic Review and a Literature Review, and why it matters by Lynn Kysh, MLIS, University of Southern California - Norris Medical Library
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The difference between a systematic review and a literature review

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Home | Blog | Best Practice | The difference between a systematic review and a literature review

Covidence takes a look at the difference between the two

Most of us are familiar with the terms systematic review and literature review. Both review types synthesise evidence and provide summary information. So what are the differences? What does systematic mean? And which approach is best 🤔 ?

‘ Systematic ‘ describes the review’s methods. It means that they are transparent, reproducible and defined before the search gets underway. That’s important because it helps to minimise the bias that would result from cherry-picking studies in a non-systematic way. 

This brings us to literature reviews. Literature reviews don’t usually apply the same rigour in their methods. That’s because, unlike systematic reviews, they don’t aim to produce an answer to a clinical question. Literature reviews can provide context or background information for a new piece of research. They can also stand alone as a general guide to what is already known about a particular topic. 

Interest in systematic reviews has grown in recent years and the frequency of ‘systematic reviews’ in Google books has overtaken ‘literature reviews’ (with all the usual Ngram Viewer warnings – it searches around 6% of all books, no journals). 

Let’s take a look at the two review types in more detail to highlight some key similarities and differences 👀.

🙋🏾‍♂️ What is a systematic review?

Systematic reviews ask a specific question about the effectiveness of a treatment and answer it by summarising evidence that meets a set of pre-specified criteria. 

The process starts with a research question and a protocol or research plan. A review team searches for studies to answer the question using a highly sensitive search strategy. The retrieved studies are then screened for eligibility using the inclusion and exclusion criteria (this is done by at least two people working independently). Next, the reviewers extract the relevant data and assess the quality of the included studies. Finally, the review team synthesises the extracted study data and presents the results. The process is shown in figure 2 .

The results of a systematic review can be presented in many ways and the choice will depend on factors such as the type of data. Some reviews use meta-analysis to produce a statistical summary of effect estimates. Other reviews use narrative synthesis to present a textual summary.

Covidence accelerates the screening, data extraction, and quality assessment stages of your systematic review. It provides simple workflows and easy collaboration with colleagues around the world.

When is it appropriate to do a systematic review?

If you have a clinical question about the effectiveness of a particular treatment or treatments, you could answer it by conducting a systematic review. Systematic reviews in clinical medicine often follow the PICO framework, which stands for:

👦 Population (or patients)

💊 Intervention

💊 Comparison

Here’s a typical example of a systematic review title that uses the PICO framework: Alarms [intervention] versus drug treatments [comparison] for the prevention of nocturnal enuresis [outcome] in children [population]

Key attributes

• Systematic reviews follow prespecified methods
• The methods are explicit and replicable
• The review team assesses the quality of the evidence and attempts to minimise bias
• Results and conclusions are based on the evidence

🙋🏻‍♀️ What is a literature review?

Literature reviews provide an overview of what is known about a particular topic. They evaluate the material, rather than simply restating it, but the methods used to do this are not usually prespecified and they are not described in detail in the review. The search might be comprehensive but it does not aim to be exhaustive. Literature reviews are also referred to as narrative reviews.

Literature reviews use a topical approach and often take the form of a discussion. Precision and replicability are not the focus, rather the author seeks to demonstrate their understanding and perhaps also present their work in the context of what has come before. Often, this sort of synthesis does not attempt to control for the author’s own bias. The results or conclusion of a literature review is likely to be presented using words rather than statistical methods.

When is it appropriate to do a literature review?

We’ve all written some form of literature review: they are a central part of academic research ✍🏾. Literature reviews often form the introduction to a piece of writing, to provide the context. They can also be used to identify gaps in the literature and the need to fill them with new research 📚.

• Literature reviews take a thematic approach
• They do not specify inclusion or exclusion criteria
• They do not answer a clinical question
• The conclusions might be influenced by the author’s own views

🙋🏽 Ok, but what is a systematic literature review?

A quick internet search retrieves a cool 200 million hits for ‘systematic literature review’. What strange hybrid is this 🤯🤯 ?

Systematic review methodology has its roots in evidence-based medicine but it quickly gained traction in other areas – the social sciences for example – where researchers recognise the value of being methodical and minimising bias. Systematic review methods are increasingly applied to the more traditional types of review, including literature reviews, hence the proliferation of terms like ‘systematic literature review’ and many more.

Beware of the labels 🚨. The terminology used to describe review types can vary by discipline and changes over time. To really understand how any review was done you will need to examine the methods critically and make your own assessment of the quality and reliability of each synthesis 🤓.

Review methods are evolving constantly as researchers find new ways to meet the challenge of synthesising the evidence. Systematic review methods have influenced many other review types, including the traditional literature review. 

Covidence is a web-based tool that saves you time at the screening, selection, data extraction and quality assessment stages of your systematic review. It supports easy collaboration across teams and provides a clear overview of task status.

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Methodology

• Systematic Review | Definition, Example, & Guide

Systematic Review | Definition, Example & Guide

Published on June 15, 2022 by Shaun Turney . Revised on November 20, 2023.

A systematic review is a type of review that uses repeatable methods to find, select, and synthesize all available evidence. It answers a clearly formulated research question and explicitly states the methods used to arrive at the answer.

They answered the question “What is the effectiveness of probiotics in reducing eczema symptoms and improving quality of life in patients with eczema?”

In this context, a probiotic is a health product that contains live microorganisms and is taken by mouth. Eczema is a common skin condition that causes red, itchy skin.

Table of contents

What is a systematic review, systematic review vs. meta-analysis, systematic review vs. literature review, systematic review vs. scoping review, when to conduct a systematic review, pros and cons of systematic reviews, step-by-step example of a systematic review, other interesting articles, frequently asked questions about systematic reviews.

A review is an overview of the research that’s already been completed on a topic.

What makes a systematic review different from other types of reviews is that the research methods are designed to reduce bias . The methods are repeatable, and the approach is formal and systematic:

• Formulate a research question
• Develop a protocol
• Search for all relevant studies
• Apply the selection criteria
• Extract the data
• Synthesize the data
• Write and publish a report

Although multiple sets of guidelines exist, the Cochrane Handbook for Systematic Reviews is among the most widely used. It provides detailed guidelines on how to complete each step of the systematic review process.

Systematic reviews are most commonly used in medical and public health research, but they can also be found in other disciplines.

Systematic reviews typically answer their research question by synthesizing all available evidence and evaluating the quality of the evidence. Synthesizing means bringing together different information to tell a single, cohesive story. The synthesis can be narrative ( qualitative ), quantitative , or both.

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Systematic reviews often quantitatively synthesize the evidence using a meta-analysis . A meta-analysis is a statistical analysis, not a type of review.

A meta-analysis is a technique to synthesize results from multiple studies. It’s a statistical analysis that combines the results of two or more studies, usually to estimate an effect size .

A literature review is a type of review that uses a less systematic and formal approach than a systematic review. Typically, an expert in a topic will qualitatively summarize and evaluate previous work, without using a formal, explicit method.

Although literature reviews are often less time-consuming and can be insightful or helpful, they have a higher risk of bias and are less transparent than systematic reviews.

Similar to a systematic review, a scoping review is a type of review that tries to minimize bias by using transparent and repeatable methods.

However, a scoping review isn’t a type of systematic review. The most important difference is the goal: rather than answering a specific question, a scoping review explores a topic. The researcher tries to identify the main concepts, theories, and evidence, as well as gaps in the current research.

Sometimes scoping reviews are an exploratory preparation step for a systematic review, and sometimes they are a standalone project.

A systematic review is a good choice of review if you want to answer a question about the effectiveness of an intervention , such as a medical treatment.

To conduct a systematic review, you’ll need the following:

• A precise question , usually about the effectiveness of an intervention. The question needs to be about a topic that’s previously been studied by multiple researchers. If there’s no previous research, there’s nothing to review.
• If you’re doing a systematic review on your own (e.g., for a research paper or thesis ), you should take appropriate measures to ensure the validity and reliability of your research.
• Access to databases and journal archives. Often, your educational institution provides you with access.
• Time. A professional systematic review is a time-consuming process: it will take the lead author about six months of full-time work. If you’re a student, you should narrow the scope of your systematic review and stick to a tight schedule.
• Bibliographic, word-processing, spreadsheet, and statistical software . For example, you could use EndNote, Microsoft Word, Excel, and SPSS.

A systematic review has many pros .

• They minimize research bias by considering all available evidence and evaluating each study for bias.
• Their methods are transparent , so they can be scrutinized by others.
• They’re thorough : they summarize all available evidence.
• They can be replicated and updated by others.

Systematic reviews also have a few cons .

• They’re time-consuming .
• They’re narrow in scope : they only answer the precise research question.

The 7 steps for conducting a systematic review are explained with an example.

Step 1: Formulate a research question

Formulating the research question is probably the most important step of a systematic review. A clear research question will:

• Allow you to more effectively communicate your research to other researchers and practitioners
• Guide your decisions as you plan and conduct your systematic review

A good research question for a systematic review has four components, which you can remember with the acronym PICO :

• Population(s) or problem(s)
• Intervention(s)
• Comparison(s)

You can rearrange these four components to write your research question:

• What is the effectiveness of I versus C for O in P ?

Sometimes, you may want to include a fifth component, the type of study design . In this case, the acronym is PICOT .

• Type of study design(s)
• The population of patients with eczema
• The intervention of probiotics
• In comparison to no treatment, placebo , or non-probiotic treatment
• The outcome of changes in participant-, parent-, and doctor-rated symptoms of eczema and quality of life
• Randomized control trials, a type of study design

Their research question was:

• What is the effectiveness of probiotics versus no treatment, a placebo, or a non-probiotic treatment for reducing eczema symptoms and improving quality of life in patients with eczema?

Step 2: Develop a protocol

A protocol is a document that contains your research plan for the systematic review. This is an important step because having a plan allows you to work more efficiently and reduces bias.

Your protocol should include the following components:

• Background information : Provide the context of the research question, including why it’s important.
• Research objective (s) : Rephrase your research question as an objective.
• Selection criteria: State how you’ll decide which studies to include or exclude from your review.
• Search strategy: Discuss your plan for finding studies.
• Analysis: Explain what information you’ll collect from the studies and how you’ll synthesize the data.

If you’re a professional seeking to publish your review, it’s a good idea to bring together an advisory committee . This is a group of about six people who have experience in the topic you’re researching. They can help you make decisions about your protocol.

It’s highly recommended to register your protocol. Registering your protocol means submitting it to a database such as PROSPERO or ClinicalTrials.gov .

Step 3: Search for all relevant studies

Searching for relevant studies is the most time-consuming step of a systematic review.

To reduce bias, it’s important to search for relevant studies very thoroughly. Your strategy will depend on your field and your research question, but sources generally fall into these four categories:

• Databases: Search multiple databases of peer-reviewed literature, such as PubMed or Scopus . Think carefully about how to phrase your search terms and include multiple synonyms of each word. Use Boolean operators if relevant.
• Handsearching: In addition to searching the primary sources using databases, you’ll also need to search manually. One strategy is to scan relevant journals or conference proceedings. Another strategy is to scan the reference lists of relevant studies.
• Gray literature: Gray literature includes documents produced by governments, universities, and other institutions that aren’t published by traditional publishers. Graduate student theses are an important type of gray literature, which you can search using the Networked Digital Library of Theses and Dissertations (NDLTD) . In medicine, clinical trial registries are another important type of gray literature.
• Experts: Contact experts in the field to ask if they have unpublished studies that should be included in your review.

At this stage of your review, you won’t read the articles yet. Simply save any potentially relevant citations using bibliographic software, such as Scribbr’s APA or MLA Generator .

• Databases: EMBASE, PsycINFO, AMED, LILACS, and ISI Web of Science
• Handsearch: Conference proceedings and reference lists of articles
• Gray literature: The Cochrane Library, the metaRegister of Controlled Trials, and the Ongoing Skin Trials Register
• Experts: Authors of unpublished registered trials, pharmaceutical companies, and manufacturers of probiotics

Step 4: Apply the selection criteria

Applying the selection criteria is a three-person job. Two of you will independently read the studies and decide which to include in your review based on the selection criteria you established in your protocol . The third person’s job is to break any ties.

To increase inter-rater reliability , ensure that everyone thoroughly understands the selection criteria before you begin.

If you’re writing a systematic review as a student for an assignment, you might not have a team. In this case, you’ll have to apply the selection criteria on your own; you can mention this as a limitation in your paper’s discussion.

You should apply the selection criteria in two phases:

• Based on the titles and abstracts : Decide whether each article potentially meets the selection criteria based on the information provided in the abstracts.
• Based on the full texts: Download the articles that weren’t excluded during the first phase. If an article isn’t available online or through your library, you may need to contact the authors to ask for a copy. Read the articles and decide which articles meet the selection criteria.

It’s very important to keep a meticulous record of why you included or excluded each article. When the selection process is complete, you can summarize what you did using a PRISMA flow diagram .

Next, Boyle and colleagues found the full texts for each of the remaining studies. Boyle and Tang read through the articles to decide if any more studies needed to be excluded based on the selection criteria.

When Boyle and Tang disagreed about whether a study should be excluded, they discussed it with Varigos until the three researchers came to an agreement.

Step 5: Extract the data

Extracting the data means collecting information from the selected studies in a systematic way. There are two types of information you need to collect from each study:

• Information about the study’s methods and results . The exact information will depend on your research question, but it might include the year, study design , sample size, context, research findings , and conclusions. If any data are missing, you’ll need to contact the study’s authors.
• Your judgment of the quality of the evidence, including risk of bias .

You should collect this information using forms. You can find sample forms in The Registry of Methods and Tools for Evidence-Informed Decision Making and the Grading of Recommendations, Assessment, Development and Evaluations Working Group .

Extracting the data is also a three-person job. Two people should do this step independently, and the third person will resolve any disagreements.

They also collected data about possible sources of bias, such as how the study participants were randomized into the control and treatment groups.

Step 6: Synthesize the data

Synthesizing the data means bringing together the information you collected into a single, cohesive story. There are two main approaches to synthesizing the data:

• Narrative ( qualitative ): Summarize the information in words. You’ll need to discuss the studies and assess their overall quality.
• Quantitative : Use statistical methods to summarize and compare data from different studies. The most common quantitative approach is a meta-analysis , which allows you to combine results from multiple studies into a summary result.

Generally, you should use both approaches together whenever possible. If you don’t have enough data, or the data from different studies aren’t comparable, then you can take just a narrative approach. However, you should justify why a quantitative approach wasn’t possible.

Boyle and colleagues also divided the studies into subgroups, such as studies about babies, children, and adults, and analyzed the effect sizes within each group.

Step 7: Write and publish a report

The purpose of writing a systematic review article is to share the answer to your research question and explain how you arrived at this answer.

Your article should include the following sections:

• Abstract : A summary of the review
• Introduction : Including the rationale and objectives
• Methods : Including the selection criteria, search method, data extraction method, and synthesis method
• Results : Including results of the search and selection process, study characteristics, risk of bias in the studies, and synthesis results
• Discussion : Including interpretation of the results and limitations of the review
• Conclusion : The answer to your research question and implications for practice, policy, or research

To verify that your report includes everything it needs, you can use the PRISMA checklist .

Once your report is written, you can publish it in a systematic review database, such as the Cochrane Database of Systematic Reviews , and/or in a peer-reviewed journal.

In their report, Boyle and colleagues concluded that probiotics cannot be recommended for reducing eczema symptoms or improving quality of life in patients with eczema. Note Generative AI tools like ChatGPT can be useful at various stages of the writing and research process and can help you to write your systematic review. However, we strongly advise against trying to pass AI-generated text off as your own work.

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

• Student’s  t -distribution
• Normal distribution
• Null and Alternative Hypotheses
• Chi square tests
• Confidence interval
• Quartiles & Quantiles
• Cluster sampling
• Stratified sampling
• Data cleansing
• Reproducibility vs Replicability
• Peer review
• Prospective cohort study

Research bias

• Implicit bias
• Cognitive bias
• Placebo effect
• Hawthorne effect
• Hindsight bias
• Affect heuristic
• Social desirability bias

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

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

A systematic review is secondary research because it uses existing research. You don’t collect new data yourself.

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• Thought for Food Blog

What is the difference between a systematic review and a systematic literature review?

By Carol Hollier on 07-Jan-2020 12:42:03

For those not immersed in systematic reviews, understanding the difference between a systematic review and a systematic literature review can be confusing.  It helps to realise that a “systematic review” is a clearly defined thing, but ambiguity creeps in around the phrase “systematic literature review” because people can and do use it in a variety of ways. 

A systematic review is a research study of research studies.  To qualify as a systematic review, a review needs to adhere to standards of transparency and reproducibility.  It will use explicit methods to identify, select, appraise, and synthesise empirical results from different but similar studies.  The study will be done in stages:  

• In stage one, the question, which must be answerable, is framed
• Stage two is a comprehensive literature search to identify relevant studies
• In stage three the identified literature’s quality is scrutinised and decisions made on whether or not to include each article in the review
• In stage four the evidence is summarised and, if the review includes a meta-analysis, the data extracted; in the final stage, findings are interpreted. [1]

Some reviews also state what degree of confidence can be placed on that answer, using the GRADE scale.  By going through these steps, a systematic review provides a broad evidence base on which to make decisions about medical interventions, regulatory policy, safety, or whatever question is analysed.   By documenting each step explicitly, the review is not only reproducible, but can be updated as more evidence on the question is generated.

Sometimes when people talk about a “systematic literature review”, they are using the phrase interchangeably with “systematic review”.  However, people can also use the phrase systematic literature review to refer to a literature review that is done in a fairly systematic way, but without the full rigor of a systematic review. 

For instance, for a systematic review, reviewers would strive to locate relevant unpublished studies in grey literature and possibly by contacting researchers directly.  Doing this is important for combatting publication bias, which is the tendency for studies with positive results to be published at a higher rate than studies with null results.  It is easy to understand how this well-documented tendency can skew a review’s findings, but someone conducting a systematic literature review in the loose sense of the phrase might, for lack of resource or capacity, forgo that step. 

Another difference might be in who is doing the research for the review. A systematic review is generally conducted by a team including an information professional for searches and a statistician for meta-analysis, along with subject experts.  Team members independently evaluate the studies being considered for inclusion in the review and compare results, adjudicating any differences of opinion.   In contrast, a systematic literature review might be conducted by one person. 

Overall, while a systematic review must comply with set standards, you would expect any review called a systematic literature review to strive to be quite comprehensive.  A systematic literature review would contrast with what is sometimes called a narrative or journalistic literature review, where the reviewer’s search strategy is not made explicit, and evidence may be cherry-picked to support an argument.

FSTA is a key tool for systematic reviews and systematic literature reviews in the sciences of food and health.

The patents indexed help find results of research not otherwise publicly available because it has been done for commercial purposes.

The FSTA thesaurus will surface results that would be missed with keyword searching alone. Since the thesaurus is designed for the sciences of food and health, it is the most comprehensive for the field. 

All indexing and abstracting in FSTA is in English, so you can do your searching in English yet pick up non-English language results, and get those results translated if they meet the criteria for inclusion in a systematic review.

FSTA includes grey literature (conference proceedings) which can be difficult to find, but is important to include in comprehensive searches.

FSTA content has a deep archive. It goes back to 1969 for farm to fork research, and back to the late 1990s for food-related human nutrition literature—systematic reviews (and any literature review) should include not just the latest research but all relevant research on a question. 

You can also use FSTA to find literature reviews.

FSTA allows you to easily search for review articles (both narrative and systematic reviews) by using the subject heading or thesaurus term “REVIEWS" and an appropriate free-text keyword.

On the Web of Science or EBSCO platform, an FSTA search for reviews about cassava would look like this: DE "REVIEWS" AND cassava.

On the Ovid platform using the multi-field search option, the search would look like this: reviews.sh. AND cassava.af.

In 2011 FSTA introduced the descriptor META-ANALYSIS, making it easy to search specifically for systematic reviews that include a meta-analysis published from that year onwards.

On the EBSCO or Web of Science platform, an FSTA search for systematic reviews with meta-analyses about staphylococcus aureus would look like this: DE "META-ANALYSIS" AND staphylococcus aureus.

On the Ovid platform using the multi-field search option, the search would look like this: meta-analysis.sh. AND staphylococcus aureus.af.

Systematic reviews with meta-analyses published before 2011 are included in the REVIEWS controlled vocabulary term in the thesaurus.

An easy way to locate pre-2011 systematic reviews with meta-analyses is to search the subject heading or thesaurus term "REVIEWS" AND meta-analysis as a free-text keyword AND another appropriate free-text keyword.

On the Web of Science or EBSCO platform, the FSTA search would look like this: DE "REVIEWS" AND meta-analysis AND carbohydrate*

On the Ovid platform using the multi-field search option, the search would look like this: reviews .s h. AND meta-analysis.af. AND carbohydrate*.af.  

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About Systematic Reviews

Understanding the Differences Between a Systematic Review vs Literature Review

Automate every stage of your literature review to produce evidence-based research faster and more accurately.

Let’s look at these differences in further detail.

Goal of the Review

The objective of a literature review is to provide context or background information about a topic of interest. Hence the methodology is less comprehensive and not exhaustive. The aim is to provide an overview of a subject as an introduction to a paper or report. This overview is obtained firstly through evaluation of existing research, theories, and evidence, and secondly through individual critical evaluation and discussion of this content.

A systematic review attempts to answer specific clinical questions (for example, the effectiveness of a drug in treating an illness). Answering such questions comes with a responsibility to be comprehensive and accurate. Failure to do so could have life-threatening consequences. The need to be precise then calls for a systematic approach. The aim of a systematic review is to establish authoritative findings from an account of existing evidence using objective, thorough, reliable, and reproducible research approaches, and frameworks.

Level of Planning Required

The methodology involved in a literature review is less complicated and requires a lower degree of planning. For a systematic review, the planning is extensive and requires defining robust pre-specified protocols. It first starts with formulating the research question and scope of the research. The PICO’s approach (population, intervention, comparison, and outcomes) is used in designing the research question. Planning also involves establishing strict eligibility criteria for inclusion and exclusion of the primary resources to be included in the study. Every stage of the systematic review methodology is pre-specified to the last detail, even before starting the review process. It is recommended to register the protocol of your systematic review to avoid duplication. Journal publishers now look for registration in order to ensure the reviews meet predefined criteria for conducting a systematic review [1].

Search Strategy for Sourcing Primary Resources

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Quality Assessment of the Collected Resources

A rigorous appraisal of collected resources for the quality and relevance of the data they provide is a crucial part of the systematic review methodology. A systematic review usually employs a dual independent review process, which involves two reviewers evaluating the collected resources based on pre-defined inclusion and exclusion criteria. The idea is to limit bias in selecting the primary studies. Such a strict review system is generally not a part of a literature review.

Presentation of Results

Most literature reviews present their findings in narrative or discussion form. These are textual summaries of the results used to critique or analyze a body of literature about a topic serving as an introduction. Due to this reason, literature reviews are sometimes also called narrative reviews. To know more about the differences between narrative reviews and systematic reviews , click here.

A systematic review requires a higher level of rigor, transparency, and often peer-review. The results of a systematic review can be interpreted as numeric effect estimates using statistical methods or as a textual summary of all the evidence collected. Meta-analysis is employed to provide the necessary statistical support to evidence outcomes. They are usually conducted to examine the evidence present on a condition and treatment. The aims of a meta-analysis are to determine whether an effect exists, whether the effect is positive or negative, and establish a conclusive estimate of the effect [2].

Using statistical methods in generating the review results increases confidence in the review. Results of a systematic review are then used by clinicians to prescribe treatment or for pharmacovigilance purposes. The results of the review can also be presented as a qualitative assessment when the end goal is issuing recommendations or guidelines.

Risk of Bias

Literature reviews are mostly used by authors to provide background information with the intended purpose of introducing their own research later. Since the search for included primary resources is also less exhaustive, it is more prone to bias.

One of the main objectives for conducting a systematic review is to reduce bias in the evidence outcome. Extensive planning, strict eligibility criteria for inclusion and exclusion, and a statistical approach for computing the result reduce the risk of bias.

Intervention studies consider risk of bias as the “likelihood of inaccuracy in the estimate of causal effect in that study.” In systematic reviews, assessing the risk of bias is critical in providing accurate assessments of overall intervention effect [3].

With numerous review methods available for analyzing, synthesizing, and presenting existing scientific evidence, it is important for researchers to understand the differences between the review methods. Choosing the right method for a review is crucial in achieving the objectives of the research.

[1] “Systematic Review Protocols and Protocol Registries | NIH Library,” www.nihlibrary.nih.gov . https://www.nihlibrary.nih.gov/services/systematic-review-service/systematic-review-protocols-and-protocol-registries

[2] A. B. Haidich, “Meta-analysis in medical research,” Hippokratia , vol. 14, no. Suppl 1, pp. 29–37, Dec. 2010, [Online]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049418/#:~:text=Meta%2Danalyses%20are%20conducted%20to

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Literature Review Research

Literature review vs. systematic review.

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Resources for Systematic Reviews

• NIH Systematic Review Protocols and Protocol Registries Systematic review services and information from the National Institutes of Health.
• Purdue University Systematic Reviews LibGuide Purdue University has created this helpful online research guide on systematic reviews. Most content is available publicly but please note that some links are accessible only to Purdue students.

It is common to confuse literature and systematic reviews because both are used to provide a summary of the existing literature or research on a specific topic. Despite this commonality, these two reviews vary significantly. The table below highlights the differences.

Kysh, Lynn (2013). Difference between a systematic review and a literature review. figshare. Poster. https://doi.org/10.6084/m9.figshare.766364.v1

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Systematic Review vs. Literature Review

4-minute read

• 28th October 2023

If you’ve been reading research papers, chances are you’ve come across two commonly used approaches to synthesizing existing knowledge: systematic reviews and literature reviews . Although they share similarities, it’s important to understand their differences to help you choose the most appropriate method for your research needs.

In this blog post, we’ll outline the key distinctions between systematic reviews and literature reviews, so that you can make an informed decision about which approach to include in your research plan . Let’s begin!

Objective and Purpose

The primary objective of a literature review is to provide an overview and summary of the existing literature on a specific topic to set the stage for your own critical evaluation . A literature review aims to identify key concepts, theories, and research findings, as well as gaps in knowledge, to establish a foundation for further studies.

On the other hand, systematic reviews have a more focused purpose. They aim to address a particular research question using a predefined methodology and criteria for study selection. Systematic reviews seek to provide a comprehensive and objective summary of the available evidence in order to draw significant conclusions.

Methodology and Process

Literature reviews often adopt a flexible and iterative approach. They utilize the analysis, evaluation, and summarization of relevant research or scholarly literature, such as journal articles, books, and conference proceedings. Researchers use various search strategies and sources to gather the material; selection criteria may be loosely defined. When undertaking the literature review, qualitative techniques are often used to identify patterns and themes.

In contrast, systematic reviews follow a more structured and replicable process. After your key research question has been fully developed, it can often be helpful to follow an analytic framework to guide your research. Extensive literature searches across multiple databases are conducted using predefined search terms and strict inclusion and exclusion criteria. Researchers critically assess the quality of research and risk of bias in each study, systematically extract and analyze the data, and may employ statistical methods, such as meta-analysis , to synthesize the findings.

Outcomes and Findings

The outcomes of literature reviews primarily include a summary of the existing literature, key findings, useful methodologies, and identified research gaps . These reviews provide a broad understanding of the current state of knowledge in a particular area and can help researchers identify directions for future studies. Literature reviews aim to describe and analyze the existing research rather than providing definitive conclusions or making recommendations.

Systematic reviews, however, produce more conclusive results. They statistically analyze the data from selected studies, often incorporating meta-analysis, in order to answer the key research question. Systematic review findings often include a summary of findings table to communicate the main outcomes as well as information about the materials that were covered in the review.

Applicability and Utility

Due to their broad nature, literature reviews are useful for researchers looking to gain an overview of a specific field or topic. They provide a foundation for understanding existing knowledge, identifying gaps, and generating research questions. Literature reviews tend to be used in the early stages of research projects or when developing theoretical frameworks for a thesis or dissertation.

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With their rigorous methodology, systematic reviews are valuable for informing evidence-based practice and decision-making. They can be used as stand-alone scientific publications to illustrate the current state of scientific evidence, set a research agenda, or inform policy-making.

If you’re trying to decide whether a systematic review or literature review is the best approach for your project, consider the main distinctions:

1. Literature reviews offer a broad overview of the existing literature and identify research gaps, while systematic reviews focus on answering a specific research question.

2. Literature reviews commonly adopt a flexible and iterative approach, while systematic reviews use a structured and rigorous approach.

3. Literature reviews identify key findings, useful methodologies, and identified research gaps. Systematic reviews, on the other hand, produce conclusive results to answer the key research question.

4. Literature reviews are often carried out early on in a thesis or dissertation to identify existing research gaps, whereas systematic reviews can stand on their own as a conclusive analysis.

Once you understand these differences, you’re ready to choose the best approach for your own research paper.

And if you’re interested in getting help with proofreading your research paper , consider our research paper editing services . You can even try a sample of our services for free . Good luck reviewing and researching!

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Systematic, Scoping, and Other Literature Reviews: Overview

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What Is a Systematic Review?

Regular literature reviews are simply summaries of the literature on a particular topic. A systematic review, however, is a comprehensive literature review conducted to answer a specific research question. Authors of a systematic review aim to find, code, appraise, and synthesize all of the previous research on their question in an unbiased and well-documented manner. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) outline the minimum amount of information that needs to be reported at the conclusion of a systematic review project. 

Other types of what are known as "evidence syntheses," such as scoping, rapid, and integrative reviews, have varying methodologies. While systematic reviews originated with and continue to be a popular publication type in medicine and other health sciences fields, more and more researchers in other disciplines are choosing to conduct evidence syntheses. 

This guide will walk you through the major steps of a systematic review and point you to key resources including Covidence, a systematic review project management tool. For help with systematic reviews and other major literature review projects, please send us an email at  [email protected] .

Getting Help with Reviews

Organization such as the Institute of Medicine recommend that you consult a librarian when conducting a systematic review. Librarians at the University of Nevada, Reno can help you:

• Understand best practices for conducting systematic reviews and other evidence syntheses in your discipline
• Choose and formulate a research question
• Decide which review type (e.g., systematic, scoping, rapid, etc.) is the best fit for your project
• Determine what to include and where to register a systematic review protocol
• Select search terms and develop a search strategy
• Identify databases and platforms to search
• Find the full text of articles and other sources
• Become familiar with free citation management (e.g., EndNote, Zotero)
• Get access to you and help using Covidence, a systematic review project management tool

Doing a Systematic Review

• Plan - This is the project planning stage. You and your team will need to develop a good research question, determine the type of review you will conduct (systematic, scoping, rapid, etc.), and establish the inclusion and exclusion criteria (e.g., you're only going to look at studies that use a certain methodology). All of this information needs to be included in your protocol. You'll also need to ensure that the project is viable - has someone already done a systematic review on this topic? Do some searches and check the various protocol registries to find out. 
• Identify - Next, a comprehensive search of the literature is undertaken to ensure all studies that meet the predetermined criteria are identified. Each research question is different, so the number and types of databases you'll search - as well as other online publication venues - will vary. Some standards and guidelines specify that certain databases (e.g., MEDLINE, EMBASE) should be searched regardless. Your subject librarian can help you select appropriate databases to search and develop search strings for each of those databases.  
• Evaluate - In this step, retrieved articles are screened and sorted using the predetermined inclusion and exclusion criteria. The risk of bias for each included study is also assessed around this time. It's best if you import search results into a citation management tool (see below) to clean up the citations and remove any duplicates. You can then use a tool like Rayyan (see below) to screen the results. You should begin by screening titles and abstracts only, and then you'll examine the full text of any remaining articles. Each study should be reviewed by a minimum of two people on the project team. 
• Collect - Each included study is coded and the quantitative or qualitative data contained in these studies is then synthesized. You'll have to either find or develop a coding strategy or form that meets your needs. 
• Explain - The synthesized results are articulated and contextualized. What do the results mean? How have they answered your research question?
• Summarize - The final report provides a complete description of the methods and results in a clear, transparent fashion. 

Adapted from

Types of reviews, systematic review.

These types of studies employ a systematic method to analyze and synthesize the results of numerous studies. "Systematic" in this case means following a strict set of steps - as outlined by entities like PRISMA and the Institute of Medicine - so as to make the review more reproducible and less biased. Consistent, thorough documentation is also key. Reviews of this type are not meant to be conducted by an individual but rather a (small) team of researchers. Systematic reviews are widely used in the health sciences, often to find a generalized conclusion from multiple evidence-based studies. 

Meta-Analysis

A systematic method that uses statistics to analyze the data from numerous studies. The researchers combine the data from studies with similar data types and analyze them as a single, expanded dataset. Meta-analyses are a type of systematic review.

Scoping Review

A scoping review employs the systematic review methodology to explore a broader topic or question rather than a specific and answerable one, as is generally the case with a systematic review. Authors of these types of reviews seek to collect and categorize the existing literature so as to identify any gaps.

Rapid Review

Rapid reviews are systematic reviews conducted under a time constraint. Researchers make use of workarounds to complete the review quickly (e.g., only looking at English-language publications), which can lead to a less thorough and more biased review. 

Narrative Review

A traditional literature review that summarizes and synthesizes the findings of numerous original research articles. The purpose and scope of narrative literature reviews vary widely and do not follow a set protocol. Most literature reviews are narrative reviews. 

Umbrella Review

Umbrella reviews are, essentially, systematic reviews of systematic reviews. These compile evidence from multiple review studies into one usable document. 

Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal , vol. 26, no. 2, 2009, pp. 91-108. doi: 10.1111/j.1471-1842.2009.00848.x .

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

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Systematic and other reviews: criteria and complexities

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1 Editor-in-Chief, Journal of Voice, Philadephia, USA

2 Editor Emeritus, Ear, Nose and Throat Journal, Philadephia, USA

Matthew L. Bush

3 Assistant Editor, Otology & Neurotology, Lexington, USA

Rakesh Chandra

4 Editor-in-Chief, Ear, Ear, Nose and Throat Journal, Nashville, USA

Douglas Chepeha

5 Editor-in-Chief, Journal of Otolaryngology – Head & Neck Surgery, Toronto, Canada

Brian Rotenberg

6 Editor-in-Chief, Journal of Otolaryngology – Head & Neck Surgery, London, Canada

Edward W. Fisher

7 Senior Editor, Journal of Laryngology and Otology, Birmingham, UK

David Goldenberg

8 Editor-in-Chief, Operative Techniques in Otolaryngology – Head and Neck Surgery, Hershey, USA

Ehab Y. Hanna

9 Editor-in-Chief, Head & Neck, Houston, USA

Joseph E. Kerschner

10 Editor-in-Chief, International Journal of Pediatric Otorhinolaryngology, Milwaukee, USA

Dennis H. Kraus

11 Co-Editor-in-Chief, Journal of Neurological Surgery Part B: Skull Base, New York, USA

John H. Krouse

12 Editor-in-Chief, Otolaryngology – Head and Neck Surgery, Philadelphia, USA

13 Editor-in-Chief, OTO-Open, Philadelphia, USA

14 Editor-in-Chief, Journal for Oto-Rhino-Laryngology, Head and Neck Surgery, Philadelphia, USA

15 Editor-in-Chief, World Journal of Otorhinolaryngology – Head and Neck Surgery, Philadelphia, USA

Michael Link

16 Co-Editor-in-Chief, Journal of Neurological Surgery Part B: Skull Base, Rochester, USA

Lawrence R. Lustig

17 Editor-in-Chief, Otology & Neurotology, New York, USA

Samuel H. Selesnick

18 Editor-in-Chief, The Laryngoscope, New York, USA

Raj Sindwani

19 Editor-in-Chief, American Journal of Rhinology & Allergy, Cleveland, USA

Richard J. Smith

20 Editor-in-Chief, Annals of Otology, Rhinology & Laryngology, Iowa City, USA

James Tysome

21 Editor-in-Chief, Clinical Otolaryngology, Cambridge, UK

Peter C. Weber

22 Editor-in-Chief, American Journal of Otolaryngology, Boston, USA

D. Bradley Welling

23 Editor-in-Chief, Laryngoscope Investigative Otolaryngology, Boston, USA

Review articles can be extremely valuable. They synthesize information for readers, often provide clarity and valuable insights into a topic; and good review articles tend to be cited frequently. Review articles do not require Institutional Review Board (IRB) approval if the data reviewed are public (including private and government databases) and if the articles reviewed have received IRB approval previously. However, some institutions require IRB review and exemption for review articles. So, authors should be familiar with their institution’s policy. In assessing and interpreting review articles, it is important to understand the article’s methodology, scholarly purpose and credibility. Many readers, and some journal reviewers, are not aware that there are different kinds of review articles with different definitions, criteria and academic impact [ 1 ]. In order to understand the importance and potential application of a review article, it is valuable for readers and reviewers to be able to classify review articles correctly.

Systematic reviews

Authors often submit articles that include the term “systematic” in the title without realizing that that term requires strict adherence to specific criteria. A systematic review follows explicit methodology to answer a well-defined research question by searching the literature comprehensively, evaluating the quantity and quality of research evidence rigorously, and analyzing the evidence to synthesize an answer to the research question. The evidence gathered in systematic reviews can be qualitative or quantitative. However, if adequate and comparable quantitative data are available then a meta-analysis can be performed to assess the weighted and summarized effect size of the studies included. Depending on the research question and the data collected, systematic reviews may or may not include quantitative meta-analyses; however, meta-analyses should be performed in the setting of a systematic review to ensure that all of the appropriate data were accessed. The components of a systematic review can be found in an important article by Moher et al. published in 2009 that defined requirements for systematic reviews and meta-analyses [ 2 ].

In order to optimize reporting of meta-analyses, an international group developed the Quality of Reporting of Meta-Analyses (QUOROM) statement at a meeting in 1996 that led to publication of the QUOROM statement in 1999 [ 3 ]. Moher et al. revised that document and re-named the guidelines the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The PRISMA statement included both meta-analyses and systematic reviews, and the authors incorporated definitions established by the Cochrane Collaboration [ 4 ]. The PRISMA statement established the current standard for systematic reviews. To qualify as a systematic review, the methods section should acknowledge use of the PRISMA guidelines, and all PRISMA components should be incorporated strictly in all facets of the paper from the research question to the discussion. The PRISMA statement includes a checklist of 27 items that must be included when reporting a systematic review or meta-analysis [ 2 ]. A downloadable version of this checklist can be used by authors, reviewers, and journal editorial staff to ensure compliance with recommended components [ 5 ]. All 27 will not be listed in this brief editorial (although authors and reviewers are encouraged to consult the article by Moher et al. and familiarize themselves with all items), but a few will be highlighted.

The research question, as reflected in the title, should be a hypothesis-based specific research inquiry. The introduction must describe the rationale for the review and provide a specific goal or set of goals to be addressed. The type of systematic review, according to the Cochrane Collaboration, is based on the research question being asked and may assess diagnostic test accuracy, review prognostic studies evidence, evaluate intervention effect, scrutinize research methodology, or summarize qualitative evidence [ 6 ].

In the methods section, the participants, interventions, comparisons, outcomes and study design (PICOS) must be put forward. In addition to mentioning compliance with PRISMA, the methods section should state whether a review protocol exists and, if so, where it can be accessed (including a registration number). Systematic reviews are eligible for registration in the International Prospective Register of Systematic Reviews (PROSPERO) as established at the University of York (York, UK). When PROSPERO is used (it is available but not required for systematic reviews), registration should occur at the initial protocol stage of the review, and the final paper should direct to the information in the register. The methods section also must include specific study characteristics including databases used, years considered, languages of articles included, specific inclusion and exclusion criteria for studies; and rationale for each criterion must be included. Which individuals specifically performed searches should be noted. Electronic search strategy (with a full description of at least one electronic search strategy sufficient to allow replication of the search), process for article selection, data variables sought, assumptions and simplifications, methods for assessing bias risk of each individual study (such as selective reporting in individual studies) and utilization of this information in data synthesis, principal summary measures (risk ratio, hazard ratio, difference in means, etc.), methods of data management and combining study results, outcome level assessment, and other information should be reported.

The results section should include the number of studies identified, screened, evaluated for eligibility (including rationale for exclusion), and those included in the final synthesis. A PRISMA flow diagram should be included to provide this information succinctly [ 7 ]. The results also should include the study characteristics, study results, risk of bias within and across studies, and a qualitative or quantitative synthesis of the results of the included studies. This level of rigor in acquiring and evaluating the evidence of each individual study is one of the criteria that distinguishes systematic reviews from other categories. If the systematic review involves studies with paired samples and quantitative data, a summary of data should be provided for each intervention group along with effect estimates and confidence intervals for all outcomes of each study. If a meta-analysis is performed, then synthesized effect size should be reported with confidence intervals and measures of consistency (i.e. – data heterogeneity such as I 2 ) for each meta-analysis, and assessment of bias risk across studies. A forest plot, which provides a graphical presentation of the meta-analysis results, should be included.

The discussion section should summarize the main findings commenting on the strength of evidence for each outcome, as well as relevance to healthcare providers, policymakers and other key stake-holders; limitations of the study and outcomes; and conclusions highlighting the interpretation of results in the context of other research, and implications for future research.

Without adhering to of all of these criteria and the others listed in the PRISMA statement and checklist, the review does not qualify to be classified as “systematic”.

Meta-analyses

Meta-analyses, when feasible based on available and comparable quantitative data, supplement a systematic review evaluation, by adding a secondary statistical analysis of the pooled weighted outcomes of similar studies. This adds a level of objectivity in the synthesis of the review’s findings. Meta-analyses are appropriate when at least 2 individual studies contain paired samples (experimental group and control group) and provide quantitative outcome data and sample size. Studies that lack a control group may over-estimate the effect size of the experimental intervention or condition being studied and are not ideal for meta-analyses [ 8 ]. It also should be remembered that the conclusions of a meta-analysis are only as valid as the data on which the analysis is based. If the articles included are flawed, then the conclusions of the meta-analysis also may be flawed. Systematic reviews and meta-analyses are the most rigorous categories of review.

Other types of reviews

Mixed methods reviews.

Systematic reviews typically contain a single type of data, either qualitative or quantitative; however, mixed methods reviews bring together a combination of data types or study types. This approach may be utilized when quantitative data, in the setting of an intervention study, only provide a narrow perspective of the efficacy or effectiveness of the intervention. The addition of qualitative data or qualitative studies may provide a more complete picture of the knowledge, attitudes, and behaviors of clinicians, patients or researchers regarding that intervention. This type of review could involve collecting either the quantitative or the qualitative data using systematic review methodology, but often the qualitative data are gathered using a convenience sampling. Many qualitative studies provide useful insights into clinical management and/or implementation of research interventions; and incorporating them into a mixed methods review may provide valuable perspective on a wide range of literature. Mixed methods reviews are not necessarily systematic in nature; however, authors conducting mixed methods reviews should follow systematic review methodology, when possible.

Literature and narrative reviews

Literature reviews include peer-reviewed original research, systematic reviews, and meta-analyses, but also may include conference abstracts, books, graduate degree theses, and other non-peer reviewed publications. The methods used to identify and evaluate studies should be specified, but they are less rigorous and comprehensive than those required for systematic reviews. Literature reviews can evaluate a broad topic but do not specifically articulate a specific question, nor do they synthesize the results of included studies rigorously. Like mixed method reviews, they provide an overview of published information on the topic, although they may be less comprehensive than integrative reviews; and, unlike systematic reviews, they do not need to support evidence-based clinical or research practices, or highlight high-quality evidence for the reader. Narrative reviews are similar to literature reviews and evaluate the same scope of literature. The terms sometimes are used interchangeably, and author bias in article selection and data interpretation is a potential concern in literature and narrative reviews.

Umbrella reviews

An umbrella review integrates previously published, high-quality reviews such as systematic reviews and meta-analyses. Its purpose is to synthesize information in previously published systematic reviews and meta-analyses into one convenient paper.

Rapid review

A rapid review uses systematic review methodology to evaluate existing research. It provides a quick synthesis of evidence and is used most commonly to assist in emergent decision-making such as that required to determine whether COVID-19 vaccines should receive emergent approval.

Scoping, mapping, and systematized reviews

If literature has not been reviewed comprehensively in a specific subject that is varied and complex, a mapping review (also called scoping review) may be useful to organize initial understanding of the topic and its available literature. While mapping reviews may be helpful in crystallizing research findings and may be published, they are particularly useful in helping to determine whether a topic is amenable to systematic review, and to help organize and direct the approach of the systematic review or other reviews of the subject. Systematized reviews are used most commonly by students. The systematized review provides initial assessment of a topic that is potentially appropriate for a systematic review, but a systematized review does not meet the rigorous criteria of a systematic review and has substantially more limited value. Additional types of reviews exist including critical review, state-of-the-art review, and others.

Reviews can be invaluable; but they also can be misleading. Systematic reviews and meta-analyses provide readers with the greatest confidence that rigorous efforts have attempted to eliminate bias and ensure validity, but even they have limitations based upon the strengths and weaknesses of the literature that they have assessed (and the skill and objectivity with which the authors have executed the review). Risks of bias, incomplete information and misinformation increase as the rigor of review methodology decreases. While review articles may summarize research related to a topic for readers, non-systematic reviews lack the rigor to answer adequately hypothesis-driven research questions that can influence evidence-based practice. Journal authors, reviewers, editorial staff, and should be cognizant of the strengths and weaknesses of review methodology and should consider them carefully as they assess the value of published review articles, particularly as they determine whether the information presented should alter their patient care.

Authors’ contributions

The author(s) read and approved the final manuscript.

Declarations

The authors declare no competing interests.

This article is co-published in the following journals: Journal of Voice, Otology & Neurotology, Ear, Nose and Throat Journal, Journal of Laryngology and Otology, Operative Techniques in Otolaryngology – Head and Neck Surgery, Head & Neck, International Journal of Pediatric Otorhinolaryngology, Journal of Neurological Surgery Part B: Skull Base, Otolaryngology – Head and Neck Surgery, World Journal of Otorhinolaryngology – Head and Neck Surgery, The Laryngoscope, American Journal of Rhinology & Allergy, Annals of Otology, Rhinology & Laryngology, Clinical Otolaryngology, American Journal of Otolaryngology, Laryngoscope Investigative Otolaryngology.

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• Citing Research

The Differences in the Review Types

Grant, M.J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. H ealth Information & Libraries Journal , 26: 91-108. https://doi.org/10.1111/j.1471-1842.2009.00848.x   The objective of this study is to provide descriptive insight into the most common types of reviews, with illustrative examples from health and health information domains.

• What Type of Review is Right for you (Cornell University)

Literature Reviews

Literature Review: it is a product and a process.

As a product , it is a carefully written examination, interpretation, evaluation, and synthesis of the published literature related to your topic. It focuses on what is known about your topic and what methodologies, models, theories, and concepts have been applied to it by others.

The process is what is involved in conducting a review of the literature.

• It is ongoing
• It is iterative (repetitive)
• It involves searching for and finding relevant literature.
• It includes keeping track of your references and preparing and formatting them for the bibliography of your thesis

• Literature Reviews (University of North Carolina at Chapel Hill) This handout will explain what literature reviews are and offer insights into the form and construction of literature reviews in the humanities, social sciences, and sciences.

Scoping Reviews

Scoping reviews are a " preliminary assessment of potential size and scope of available research literature . Aims to identify nature and extent of research evidence (usually including ongoing research)." Grant and Booth (2009).

Scoping reviews are not mapping reviews: Scoping reviews are more topic based and mapping reviews are more question based.

• examining emerging evidence when specific questions are unclear - clarify definitions and conceptual boundaries
• identify and map the available evidence
• a scoping review is done prior to a systematic review
• to summarize and disseminate research findings in the research literature
• identify gaps with the intention of resolution by future publications

• Scoping review timeframe and limitations (Touro College of Pharmacy

Systematic Reviews

Many evidence-based disciplines use ‘systematic reviews," this type of review is a specific methodology that aims to comprehensively identify all relevant studies on a specific topic, and to select appropriate studies based on explicit criteria . ( https://cebma.org/faq/what-is-a-systematic-review/ )

• clearly defined search criteria
• an explicit reproducible methodology
• a systematic search of the literature with the defined criteria met
• assesses validity of the findings - no risk of bias
• a comprehensive report on the findings, apparent transparency in the results

• Better evidence for a better world Browsable collection of systematic reviews
• Systematic Reviews in the Health Sciences by Molly Maloney Last Updated Jan 8, 2024 368 views this year
• Next: Framework, Protocol, and Writing Steps >>

• En español – ExME
• Em português – EME

Traditional reviews vs. systematic reviews

Posted on 3rd February 2016 by Weyinmi Demeyin

Millions of articles are published yearly (1) , making it difficult for clinicians to keep abreast of the literature. Reviews of literature are necessary in order to provide clinicians with accurate, up to date information to ensure appropriate management of their patients. Reviews usually involve summaries and synthesis of primary research findings on a particular topic of interest and can be grouped into 2 main categories; the ‘traditional’ review and the ‘systematic’ review with major differences between them.

Traditional reviews provide a broad overview of a research topic with no clear methodological approach (2) . Information is collected and interpreted unsystematically with subjective summaries of findings. Authors aim to describe and discuss the literature from a contextual or theoretical point of view. Although the reviews may be conducted by topic experts, due to preconceived ideas or conclusions, they could be subject to bias.

Systematic reviews are overviews of the literature undertaken by identifying, critically appraising and synthesising results of primary research studies using an explicit, methodological approach(3). They aim to summarise the best available evidence on a particular research topic.

The main differences between traditional reviews and systematic reviews are summarised below in terms of the following characteristics: Authors, Study protocol, Research question, Search strategy, Sources of literature, Selection criteria, Critical appraisal, Synthesis, Conclusions, Reproducibility, and Update.

Traditional reviews

• Authors: One or more authors usually experts in the topic of interest
• Study protocol: No study protocol
• Research question: Broad to specific question, hypothesis not stated
• Search strategy: No detailed search strategy, search is probably conducted using keywords
• Sources of literature: Not usually stated and non-exhaustive, usually well-known articles. Prone to publication bias
• Selection criteria: No specific selection criteria, usually subjective. Prone to selection bias
• Critical appraisal: Variable evaluation of study quality or method
• Synthesis: Often qualitative synthesis of evidence
• Conclusions: Sometimes evidence based but can be influenced by author’s personal belief
• Reproducibility: Findings cannot be reproduced independently as conclusions may be subjective
• Update: Cannot be continuously updated

Systematic reviews

• Authors: Two or more authors are involved in good quality systematic reviews, may comprise experts in the different stages of the review
• Study protocol: Written study protocol which includes details of the methods to be used
• Research question: Specific question which may have all or some of PICO components (Population, Intervention, Comparator, and Outcome). Hypothesis is stated
• Search strategy: Detailed and comprehensive search strategy is developed
• Sources of literature: List of databases, websites and other sources of included studies are listed. Both published and unpublished literature are considered
• Selection criteria: Specific inclusion and exclusion criteria
• Critical appraisal: Rigorous appraisal of study quality
• Synthesis: Narrative, quantitative or qualitative synthesis
• Conclusions: Conclusions drawn are evidence based
• Reproducibility: Accurate documentation of method means results can be reproduced
• Update: Systematic reviews can be periodically updated to include new evidence

Decisions and health policies about patient care should be evidence based in order to provide the best treatment for patients. Systematic reviews provide a means of systematically identifying and synthesising the evidence, making it easier for policy makers and practitioners to assess such relevant information and hopefully improve patient outcomes.

• Fletcher RH, Fletcher SW. Evidence-Based Approach to the Medical Literature. Journal of General Internal Medicine. 1997; 12(Suppl 2):S5-S14. doi:10.1046/j.1525-1497.12.s2.1.x. Available from:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1497222/
• Rother ET. Systematic literature review X narrative review. Acta paul. enferm. [Internet]. 2007 June [cited 2015 Dec 25]; 20(2): v-vi. Available from: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-21002007000200001&lng=en. http://dx.doi.org/10.1590/S0103-21002007000200001
• Khan KS, Ter Riet G, Glanville J, Sowden AJ, Kleijnen J. Undertaking systematic reviews of research on effectiveness: CRD’s guidance for carrying out or commissioning reviews. NHS Centre for Reviews and Dissemination; 2001.

Weyinmi Demeyin

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No Comments on Traditional reviews vs. systematic reviews

THE INFORMATION IS VERY MUCH VALUABLE, A LOT IS INDEED EXPECTED IN ORDER TO MASTER SYSTEMATIC REVIEW

Thank you very much for the information here. My question is : Is it possible for me to do a systematic review which is not directed toward patients but just a specific population? To be specific can I do a systematic review on the mental health needs of students?

Hi Rosemary, I wonder whether it would be useful for you to look at Module 1 of the Cochrane Interactive Learning modules. This is a free module, open to everyone (you will just need to register for a Cochrane account if you don’t already have one). This guides you through conducting a systematic review, with a section specifically around defining your research question, which I feel will help you in understanding your question further. Head to this link for more details: https://training.cochrane.org/interactivelearning

I wonder if you have had a search on the Cochrane Library as yet, to see what Cochrane systematic reviews already exist? There is one review, titled “Psychological interventions to foster resilience in healthcare students” which may be of interest: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013684/full You can run searches on the library by the population and intervention you are interested in.

I hope these help you start in your investigations. Best wishes. Emma.

La revisión sistemática vale si hay solo un autor?

HI Alex, so sorry for the delay in replying to you. Yes, that is a very good point. I have copied a paragraph from the Cochrane Handbook, here, which does say that for a Cochrane Review, you should have more than one author.

“Cochrane Reviews should be undertaken by more than one person. In putting together a team, authors should consider the need for clinical and methodological expertise for the review, as well as the perspectives of stakeholders. Cochrane author teams are encouraged to seek and incorporate the views of users, including consumers, clinicians and those from varying regions and settings to develop protocols and reviews. Author teams for reviews relevant to particular settings (e.g. neglected tropical diseases) should involve contributors experienced in those settings”.

Thank you for the discussion point, much appreciated.

Hello, I’d like to ask you a question: what’s the difference between systematic review and systematized review? In addition, if the screening process of the review was made by only one author, is still a systematic or is a systematized review? Thanks

Hi. This article from Grant & Booth is a really good one to look at explaining different types of reviews: https://onlinelibrary.wiley.com/doi/10.1111/j.1471-1842.2009.00848.x It includes Systematic Reviews and Systematized Reviews. In answer to your second question, have a look at this Chapter from the Cochrane handbook. It covers the question about ‘Who should do a systematic review’. https://training.cochrane.org/handbook/current/chapter-01

A really relevant part of this chapter is this: “Systematic reviews should be undertaken by a team. Indeed, Cochrane will not publish a review that is proposed to be undertaken by a single person. Working as a team not only spreads the effort, but ensures that tasks such as the selection of studies for eligibility, data extraction and rating the certainty of the evidence will be performed by at least two people independently, minimizing the likelihood of errors.”

I hope this helps with the question. Best wishes. Emma.

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Literature Review vs Systematic Review

Literature review vs. systematic review.

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“In evidence-based practice, systematic reviews are considered one of the highest levels of information.” - Kysh, Lynn (2013): Difference between a systematic review and a literature review. [figshare]. Available at:  http://dx.doi.org/10.6084/m9.figshare.766364

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Review article, equity in park green spaces: a bibliometric analysis and systematic literature review from 2014-2023.

• 1 Ecological Technique and Engineering College, Shanghai Institute of Technology, Shanghai, China
• 2 Pan Tianshou College of Architecture, Art and Design, Ningbo University, Ningbo, China

With the global increase in population and the accelerated process of urbanization, the equitable access to park green spaces by diverse communities has become a growing concern. In order to provide an overview of the developmental trends, research focal points, and influencing factors in the study of equity in park green spaces, this paper employs bibliometric analysis and the visualization software CiteSpace to systematically analyze relevant literature in the Web of Science core database from 2014 to December 2023. The findings reveal an increasing emphasis on the research of equity in park green spaces, delineated into two distinct phases: a period of gradual exploration (2014–2018) followed by rapid development (2018 to present). Key nations contributing to research in this domain include China, the United States, and Germany. Currently, the research focus in this field primarily centers on the analysis of park green space equity based on primary social fairness, analysis of park green space equity based on vulnerable groups, and the relationship between park green spaces and health. The influencing factors of park green space equity mainly involve regional economic factors and government planning, as well as residents’ economic capabilities and racial discrimination. Future research directions could include studying park green space equity among different demographic groups, emerging assessment methods and data, park green space equity based on perceived accessibility, and the relationship between park green space equity and surface temperature.

1 Introduction

In accordance with the latest United Nations report, over 56% of the global population currently resides in urban areas, with an anticipated projection that urban populations will constitute 70% of the world’s total population by 2050 ( UN-Habitat, 2022 ). Throughout the process of urbanization, extensive land development has inflicted severe damage upon the ecological environment, resulting in a reduction of biodiversity and a decline in air quality. Research indicates that urban parks and green spaces have yield diverse benefits by providing a secure habitat and favorable living conditions for various species, preserving the ecological balance of urban areas, improving air quality ( Kroeger et al., 2014 ), and mitigating the urban heat island effect ( Donovan and Butry, 2009 ).

As integral components of urban ecosystems and pivotal platforms for recreational activities, park green spaces play a crucial role in ensuring the sustainable development of cities. However, the widening gap between socioeconomic classes has led to conspicuous inequalities in the distribution and utilization of these spaces among different societal groups. The equity of park green spaces has gradually become a significant indicator for measuring social sustainability, attracting widespread attention from academia, government bodies, and even the planning sector. For instance, the European Environment Agency recommends that urban residents should have access to green spaces within a 15-min walk, equivalent to approximately 900–1,000 m ( Stanners and Bourdeau, 1995 ). Some scholars propose the 3–30-300 rule, suggesting that everyone should be able to see at least 3 mature trees from their home; there should be a tree canopy cover of at least 30% nearby; and individuals should reside within a 300-m radius of high-quality public green spaces (covering at least 0.5 ha) ( Browning et al., 2024 ). In the United Kingdom, urban residents are suggested to have 2 ha of urban green supply within a 300-m radius of their residences ( Handley et al., 2003 ). Nevertheless, some of these recommendations for park green spaces provision may be impractical, and assessing equity standards may entail diverse needs within different cultural backgrounds and regional environments, rendering the evaluation of equity in park green spaces complex and multifaceted.

Scientific knowledge mapping is a visual representation of the development process and structural relationships within a specific field of knowledge. CiteSpace is an information visualization software designed to analyze scientific knowledge maps of literature related to a particular research topic. It generates visual maps by selecting specific information such as authors, institutions, keywords, or co-citations, allowing for the analysis of the current status, hotspots, and forefront directions of research in the field ( Chen, 2017 ). Although scholars have conducted analyses of citation and co-occurrence relationships among relevant literature using CiteSpace, these analyses have been limited to a simple interpretation and factual presentation of scientific knowledge graphs and bibliometric results, with constraints on the detailed content analysis of specific articles. With the increasing emphasis on research regarding park green spaces and their equity, a growing body of research outcomes is emerging. An analysis of the current status, hotspots, influencing factors, and dynamic frontiers of equity in park green spaces is beneficial for understanding the theoretical underpinnings and trends of this field, contributing significantly to the advancement of global sustainable development.

Therefore, this paper utilizes bibliometric analysis and content analysis, employing CiteSpace for literature measurement and visualization, to quantitatively analyze the current state of equity in park green spaces research. It seeks to summarize and categorize research hotspots, influencing factors, and frontiers. The objectives of this study include: 1) providing a comprehensive review and extension of the concept and content of equity in park green spaces; 2) quantifying and elucidating the publication timeline, contributing countries, research hotspots, and themes in equity of park green space research; 3) delving into the influencing factors of equity in park green space; 4) highlighting key research areas within the three aforementioned directions; 5) acknowledging the limitations, future prospects, and challenges of this study. The results aim to offer valuable insights for the future global planning and management of park green spaces, providing theoretical guidance for advancing equity in park green space research.

2 Conceptual

2.1 the concept of equity in park green spaces, 2.1.1 park green spaces.

This paper, following the definition of Park Green Spaces outlined in China’s ‘Classification Standard for Urban Green Spaces’ (CJJT85-2017) ( Standard for Classification of Urban Green Space, 2017 ), defines Park green spaces as areas open to the public primarily for recreational purposes, while also serving ecological, landscape, cultural, educational, and emergency evacuation functions, with certain recreational and service facilities.

2.1.2 Equity in park green spaces

In the 1970s, significant inequities emerged in western countries, with growing disparities based on gender, class, and ethnicity. William Lucy’s ( Lucy, 1981 ) “Five Subconcepts” and Bruce E. Wicks’ ( Wicks and Crompton, 1986 ) “Three Criteria” were representative theoretical frameworks in the study of fairness during that period. They argued that the allocation of public resources should consider both quantity and location, ensuring equal opportunities for everyone based on meeting minimum needs standards. Towards the end of the 20th century, in response to the social phenomenon of class stratification, scholars such as Chun Man Cho (2003) ( Cho, 2004 ) proposed that Park green spaces should be distributed equitably among different spatial units, income levels, racial and political groups, with due consideration to the specific needs of marginalized populations. From these scholars’ arguments, we can observe a shift in the concept of fairness from mere equality towards justice. This signifies a deepening understanding of fairness and reflects the current societal development, which involves the differentiation of social group needs.

2.2 Content and development of equity in park green spaces

The public nature of park green spaces determines their recognition as a form of public service. Therefore, this article draws on the research on equity in public services to clarify the content of equity in park green spaces. The following Table 1 is a compilation of research findings from scholars:

TABLE 1 . Scholars’ perception of the equity of park green spaces.

Based on the historical stages of modern societal development, this article categorizes the content of equity in park green spaces into three phases, as illustrated in Figure 1 :

1. Before the 1970s, international mainstream research focused on territorial equality, specifically the comparison of per capita park green space indicators across different regions.

2. From the 1970s to the 1990s, attention shifted to distribution balance, specifically the issue of spatial distribution balance of urban park green spaces in different geographical areas.

3. After the end of the 20th century, research on social equity differentiated into two directions: primary social equity, focusing on the differences in the ability and opportunities of different groups to access park green space services, and advanced social equity, advocating for providing park green spaces precisely based on the needs of different groups.

FIGURE 1 . The main phase of the equity in park green space study.

The article highlights that identifying the components of equity also requires corresponding to the historical stages of socio-economic development. Exploring the historical reasons behind the formation of the concept of equity is beneficial for cities in different countries and regions to recognize the current issues regarding equity based on their respective developmental stages. This understanding can assist in formulating practical and actionable strategies for future development. Therefore, it becomes essential to analyze the social context associated with these studies: before the 1970s, western societies were in a period of post-war reconstruction with government-led elite decision-making. The focus was on increasing the quantity and layout of park green spaces. However, since the 1970s, western societies have transitioned towards postmodernity, challenging elite decision-making and giving more importance to the actual needs of the public. Nevertheless, this stage also had its limitations: the understanding of public needs was relatively simplistic, and studies on the accessibility of park green spaces and the formulation of public policies often relied on a basic assumption that easy transportation would meet the public’s needs. Since the end of the 20th century, sociological research has become more complex, with social stratification and cultural diversification leading to diversified demands, and the differentiation of needs among different social groups. Identifying the needs of different groups and providing more precise services for them has become the focus of research. Besides historical reasons, the equity phased development is also associated with advancements in science and technology. In the 1990s and 2000s, continuous enhancements and optimizations of GIS technology and analytical models, along with the refinement of big data and Internet maps, made spatial fairness analysis feasible across diverse demographics. Scholars began exploring from the standpoint of various demographic needs. With the expansion of Chinese cities and an aging population, the Chinese government has proposed a strategy for common prosperity through the equalization of basic public services, incorporating green equity into residential living circle planning. The research on equity has also rapidly progressed from the first and second stages towards the third stage.

3 Materials and methods

3.1 search methodology.

This study draws upon the Web of Science (WOS) core collection database as the primary data source. In pursuit of a comprehensive compilation of relevant literature on equity in park green space, a refined search strategy was formulated by incorporating synonymous terms associated with parks, green spaces, and equity. After several adjustments, the ultimate search string adopted was TS= (“park green space*" OR “urban green space*" OR “urban park*" OR “green space*") AND (“equity*" OR “justice*" OR “accessibility*"). The selected document types were restricted to “Article” and “Review Article”. The temporal scope spans from 2014 to December 2023, with the search conducted on 10 December 2023, 1,168 articles were retrieved through the search.

3.2 Article inclusion criteria

To ensure the quality and relevance of the retrieved articles, each of the three authors conducted a detailed examination of the titles and abstracts of every potential article. Articles meeting the following inclusion criteria were then downloaded:

1. The study focused on park green space, encompassing various types such as comprehensive parks, community parks, and recreational gardens (According to China’s ‘Classification Standard for Urban Green Spaces’ CJJT85-2017 (2017), a comprehensive park refers to an area with an area ≥5 h m 2 , suitable for various outdoor activities, and equipped with comprehensive recreational and supporting management service facilities.);

2. The content addressed issues related to fairness, accessibility, spatial justice, or other relevant aspects of park green space;

3. The article was published in English and had full-text availability.

Articles not meeting these criteria were excluded from the analysis. The data collection, screening, and analysis adhered to the outlined evaluation criteria, and any disputed articles were thoroughly discussed among all co-authors until a consensus was reached. Finally, 333 articles met the inclusion criteria ( Figure 2A ), comprising 319 articles and 14 reviews ( Figure 2B ).

FIGURE 2 . Bibliometric analysis. (A) Flowchart for screening retrieved articles. (B) Number and type of articles.

3.3 Bibliometric analysis combined with content analysis

This article will utilize CiteSpace 6.2.4 and employ both bibliometric analysis and content analysis methods to comprehensively illustrate the current research status and development trends of park green space equity from multiple perspectives. The specific structure of this paper is outlined as follows (see Figure 3 ). Firstly, in Section Four, a bibliometric analysis utilizing CiteSpace is employed to examine publication timelines, contributing countries, and high-frequency keywords, accompanied by brief explanations. Subsequently, Sections Five and Six adopt content analysis to systematically review selected literature in terms of research hotspots and influencing factors. Finally, Section Seven analyzes the limitations, prospects, and challenges of the study.

FIGURE 3 . Flowchart of research methodology.

3.4 CiteSpace parameters

The bibliometric analysis of the dataset was conducted using CiteSpace 6.2.4. The “Full Record and Cited References” option was selected. Subsequently, the source data from the Web of Science (WOS) database was exported in “Plain text file” format and imported into CiteSpace. The parameter settings were configured as follows: ‘Time Slicing = From 2014, JAN To 2023, DEC' (The time range of the literature.), “Node Types = Country OR Keyword” (Selecting to conduct either country of publication analysis or keyword analysis.), “Pruning = Pathfinder AND Pruning sliced networks AND Pruning the merged network” (Trimming each slice and merging networks to highlight important network structures). All other parameters were kept at their default values.

4 Bibliometric review of equity in park green spaces

4.1 bibliometric analysis, 4.1.1 annual publication trend.

From 2014 to the present, based on the analysis of publication timelines (see Figure 4 ), the research can be categorized into the following two major phases:

• Exploratory Phase (2014–2018): This period, also referred to as the foundational research phase, witnessed a gradual fluctuation and growth in the annual publication volume of articles related to equity in park green space. Following a substantial period of applied research and foundational consolidation, the fundamental concepts and measurement methodologies of equity in park green space have essentially crystallized.

• Rapid Development Phase (2019-Present): The period from 2019 to 2023 (264 articles) represents nearly four times the number of articles from 2014 to 2018 (69 articles), there has been an exponential surge in publication volume, owing to the availability of refined network data from sources such as big data and internet mapping. Scholars have commenced endeavors to analyze the equity of parks and green spaces from the perspective of resident demand. Grounded in GIS analysis, this phase has evolved to encompass four major categories: container models, coverage models, gravity models, and two-step mobility search models (refer to Table 2 ). The significance of equity in park green space has progressively gained prominence.

FIGURE 4 . Annual publications from 2014 to 2023.

TABLE 2 . The summary of accessibility evaluation models.

4.1.2 Study countries

The node types were set to “country” (Node Types = country), and a temporal chart of publishing countries, delineated by the top 10 contributors, was generated (see Figure 5 ). In this network, N = 57 and E = 73, indicating scholarly contributions from 57 countries and regions globally with the formation of 73 collaborative relationships. In the publication country time zone graph, each country’s vertical alignment with the years represents the year of their first publication. The size of a country’s node corresponds to the total number of publications. Figure 5 reveals that several countries, including the United States, the United Kingdom, and Germany, initiated research in this field by publishing articles in 2014, followed by Chinese scholars in 2015. Notably, since 2017, Chinese scholars have exhibited a remarkable surge in publications (168), surpassing the United States and experiencing a substantial growth (see Figure 6 ). China’s total publication count is nearly three times that of the second-ranking United States (56) and more than five times that of the third-ranking Germany (30). However, as indicated by Table 3 , China demonstrates lower centrality, signifying a deficit in international collaboration. Spain exhibits the highest centrality, maintaining close academic exchanges with nations worldwide, followed by Australia and the United States (The closer the collaboration between one country and others, the higher its centrality).

FIGURE 5 . Time-zone view of contributing countries.

FIGURE 6 . Number of publications annually of the top five countries.

TABLE 3 . Top 10 countries in the field of equity in park green spaces from 2014 to 2023.

4.2 Analysis of research hotspots

4.2.1 keyword co-occurrence analysis.

The node types were designated as ‘keyword’ (Node Types = keyword), and a co-occurrence chart of high-frequency keywords (with a frequency of 15 or more) was generated (see Figure 7 ). The co-occurrence analysis graph primarily exists in the form of nodes and connecting lines. When keywords appear in the same papers, there is a connection between the two nodes. The size of a node indicates the frequency of occurrence of that keyword. The varying sizes of different-colored rings representing a specific keyword correspond to the volume of publications for different years, with the pink ring indicating high centrality of the keyword. The analysis of keyword co-occurrence serves to unveil research hotspots and frontiers within this domain. In addition to thematic terms, high-frequency keywords predominantly encompass the following categories:

• Health and Physical Activity: “health (89 occurrences),” “public health (27 occurrences),” “mental health (17 occurrences),” “healthcare (19 occurrences),” “physical activity (95 occurrences).”

• Ecological Environment: “ecosystem services (65 occurrences),” “environment (24 occurrences),” “exposure (15 occurrences).”

• Human Element: “people (16 occurrences).”

FIGURE 7 . Keyword co-occurrence analysis.

These findings indicate that, as research delves deeper, amidst the intensification of urbanization and environmental degradation, future studies are likely to witness an increase in research focused on the relationship between the ecological services of parks and green spaces and public health. Emphasis will particularly be placed on understanding the needs of different demographic groups.

4.2.2 Keyword clustering timeline analysis

Building upon the keyword co-occurrence analysis ( Figure 8 ), Selecting ‘K' AND ‘LLR,’ we conducted clustering of literature keywords, using the log-likelihood ratio (LLR) algorithm to identify top-ranking terms as cluster labels. The keyword cluster timeline provides an analytical summary of the primary research directions in the development of equity in park green space over time (see Figure 8 ). In this representation, 15 lines correspond to 15 clusters, and the position of each circle denotes the year of the first appearance of the respective keyword. Arc-shaped connecting lines indicate instances where two keywords co-occurred in the same article. The weighted mean silhouette (S = 0.8794) and modularity (Q = 0.7237) obtained from the cluster analysis signify a significant clustering structure (If S value is greater than 0.5, then the clustering result is considered reasonable; Q value between 0.3 and 1 indicates that the group structure divided by the clustering analysis is significant, with higher values being better.), indicating rational results ( Chaomei, 2005 ). As shown in Figure 8 , the 15 axes represent 15 clusters, with the position of each circle indicating the year of the first appearance of the respective keyword. Arc-shaped connecting lines represent instances where these two keywords appeared in the same paper.

FIGURE 8 . Keyword clustering timeline map.

From Figure 8 , it is evident that clusters such as #2 environmental equity, #3 environmental justice, #5 walking distance, and #13 green spaces have consistently been the research hotspots in the field of equity in park green space from 2014 to the present. Additionally, clusters like #0 mobile phone data, #1 geographically weighted regression, #4 variable catchment size, and #12 environmental gentrification, although starting later, have sustained ongoing research, indicating scholars’ enduring interest in exploring equity in park green space using various data and models, including the associated phenomenon of gentrification. The cluster #15 land surface temperature appeared later, has the shortest duration, and is still in the early stages of development, not yet forming symbiotic relationships with other clusters.

5 Research hotspots

Based on the focal points identified in the keyword co-occurrence analysis and keyword clustering timeline analysis summarized in Section 4.2 , the research highlights in the field of park green space equity can be categorized into three main areas: analysis of park green space equity based on primary social fairness, analysis of park green space equity focusing on vulnerable groups, and the relationship between park green spaces and health.

5.1 Analysis of park green space equity based on primary social fairness

Based on the content analysis and extension in Section 2.2 , it is evident that the analysis of park green space equity based on primary social fairness primarily focuses on the disparities in the ability and opportunity of different groups to access park green space services. The analytical approach is based on the multidimensional characteristics of park green spaces, such as quantity, quality, and type, as well as the demographic attributes of social groups within spatial units, to assess the ease of access to park green spaces for different social groups (whether different social groups can fairly enjoy access to park green spaces), thus determining equity.

The conclusions can be broadly categorized into two main types (see Table 4 ). The most common finding is the inequity of park green spaces, manifested in lower accessibility for the elderly, children, immigrants, and ethnic minority groups. Areas with higher housing prices tend to have higher accessibility to park green spaces, and park green space accessibility is higher in city centers compared to suburbs. However, very few studies fail to confirm the existence of park green space inequity. Some scholars attribute this to the different spatial scales used in research. Common research scales include streets, neighborhoods, and residential areas. Different spatial scales within the same city may yield different results, especially when the area of aggregation units far exceeds residents’ walking distances, which may lead to erroneous conclusions. Therefore, accessibility analysis should be conducted at finer scales whenever possible.

TABLE 4 . Analysis of park green space equity based on primary social fairness.

5.2 Analysis of park green space equity focusing on vulnerable groups

The focus of research on park green space equity has gradually shifted towards socially vulnerable groups such as low-income individuals, migrant workers, as well as physiologically vulnerable groups including children, the elderly, and women. Studies suggest that residents with lower socioeconomic status (SES) spend more time using parks and green spaces ( Shen et al., 2017 ). Moreover, Black residents have access to more parks than White residents, but the per capita park area is lower for Black residents. This phenomenon is attributed to parks in predominantly Black communities being more crowded, especially in metropolitan areas ( Julia et al., 2021 ). Faced with this inequality, if the government constructs a large number of parks and green spaces in areas lacking greenery, it can make surrounding residences more attractive, leading to an increase in housing prices, escalating living costs, and even displacement of original residents, ultimately resulting in gentrification ( Boone et al., 2009 ). Noteworthy examples include the High Line park in the United States ( Brisman, 2012 ) and the Cheonggyecheon Stream restoration project in South Korea ( Lim et al., 2013 ). To address this issue, scholars propose the “Just green enough” strategy, advocating for the construction of small-scale, dispersed parks and green spaces rather than large expanses ( Curran and Hamilton, 2012 ).

Chinese scholars, however, present two divergent views on this matter. One perspective suggests that vulnerable groups are gradually moving away from parks and green spaces. For instance, research indicates that park accessibility is negatively correlated with building age and positively correlated with housing prices ( Yu et al., 2020 ). Community parks built in earlier years exhibit higher accessibility, but in recent housing development, the elderly are increasingly distancing themselves from parks and green spaces. The other perspective contends that compared to ordinary residents, vulnerable groups such as immigrants, the unemployed, and residents of welfare housing are more likely to live in areas with better park usage rights ( Nesbitt et al., 2019 ). Two main reasons account for this: first, it is related to the urban green space planning strategy of Shanghai, which emphasizes even distribution of public green space; second, vulnerable groups reside in high-rise buildings in the city center, and although they have better park green space accessibility, their living conditions are extremely poor due to poor economic conditions. Concurrently, with the increasingly severe aging population in China, the elderly face a serious shortage of park green space usage. Studies reveal that different modes of transportation and varying park green space sizes can influence the degree of fairness in elderly people’s access to these spaces ( Meng et al., 2020 ). Addressing this issue, some scholars advocate for greater government leadership in planning, giving priority to the interests of vulnerable groups ( Hewko et al., 2002 ).

5.3 The relationship between park green space and health

The research is primarily categorized into two main areas: the relationship between park green space accessibility and health, and the relationship between park green space ecological services and health.

According to Table 5 , research on the relationship between park green space accessibility and health in China mainly focuses on large cities such as Beijing and ice and snow cities such as Harbin, as well as in Western countries like the United States, the United Kingdom, and Canada. Health data is primarily obtained through questionnaire surveys, face-to-face interviews, and publicly available databases. Some scholars have studied the relationship between park green space equity and resident health from the perspectives of accessibility, distance, and coverage. The majority of research findings indicate a positive effect of park green space equity on residents’ psychological and physiological health ( Wolch et al., 2014 ; Dadvand et al., 2016 ; Rigolon, 2016 ). Park green space accessibility is negatively correlated with the incidence of various diseases among residents ( Kaczynski and Henderson, 2007 ), particularly cardiovascular and cerebrovascular diseases ( Haiya, 2011 ). However, individual studies suggest no correlation between park green space accessibility, proportion, supply-demand ratio, and health.

TABLE 5 . The association between accessibility of PGS and health.

The relationship between park green space ecological services and health has been explored by scholars. Some researchers ( Zhang et al., 2021c ) have conducted a review and summary of international research findings, outlining the promotion benefits of green spaces on health, factors influencing the effectiveness of health impacts, and mechanisms by which green spaces promote health. Others have delved into the physiological, psychological, and social correlations between green spaces and human health, proposing the concept of green medicine and discussing auxiliary approaches to maintaining the physical and mental health of urban residents ( Kaczynski et al., 2008 ).

6 Analysis of factors influencing equity in park green spaces

The factors influencing equity in park green spaces are both significant and complex, primarily involving regional economy and government planning, as well as residents’ economic capacity.

6.1 Regional economy and government planning

The influence of regional economy on the equity of park green spaces is primarily manifested in the level of supply. In China, as a vast country with uneven development, significant disparities exist between urban and rural areas, as well as between eastern and western regions, and between the north and south. In economically developed areas, local governments often possess more financial resources, enabling them to provide more park green space resources, thereby ensuring relatively sufficient supply in these areas ( Li et al., 2018 ). For instance, the central and southeastern coastal regions typically maintain higher levels of park green space coverage. However, in areas with harsh geographical conditions or relatively underdeveloped economies, such as mountainous or desert regions, constraints on park green space construction are considerable, resulting in inadequate supply, and in some cases, levels even below the national average ( Chen and Wang, 2013 ; Zhao et al., 2013 ). Conversely, in Western countries like the United States, park green space construction is typically funded through mechanisms such as property taxes. Nevertheless, due to limited local funds, there is often a need to seek financial support from non-profit organizations, institutions, and federal governments at the national and state levels ( Harnik and Barnhart, 2015 ). This competitive allocation of funds may exacerbate inequalities ( Joassart-Marcelli et al., 2011 ), with affluent areas receiving more support, further aggravating disparities in park green space distribution.

Government planning plays a crucial role in the spatial layout and construction of park green spaces. Unlike Western countries, where park green spaces are typically planned and constructed by the government and open to the public free of charge, in China, traditional planning tends to rely on metrics like per capita park area to gauge the level of supply. Consequently, park green spaces are often densely concentrated in areas with high population density, while areas with lower population density experience shortages ( Liyan et al., 2023 ). Furthermore, some local governments, in pursuit of political achievements and prestige, may excessively prioritize increasing park green space coverage, investing heavily in superficial projects, thereby neglecting the actual needs and usage patterns of park green spaces ( Zhao et al., 2013 ). This detachment between park green space planning and residents’ demands exacerbates the disparities between planning intentions and community needs ( Chen et al., 2017 ).

6.2 The economic capacity of residents

In China, park green spaces are often closely linked to high-quality housing, with high-quality parks typically adjacent to upscale residences, while lower-quality parks are connected to relatively lower-end housing. Higher-income groups usually have the ability to purchase premium housing, thus enjoying access to better-quality park green spaces. Conversely, lower-income groups may only reside in environments with poorer-quality housing, leading to disparities in park green space utilization among residents of different socioeconomic statuses, further exacerbating spatial inequalities in park green space distribution ( Chen et al., 2020 ; Wu and Rowe, 2022 ). Studies in Western countries have also confirmed this observation, showing that in capitalist societies, higher socioeconomic status (SES) groups typically have access to larger and higher-quality park green spaces, while lower SES groups often lack equivalent opportunities ( Zhu and Zhang, 2008 ; Alessandro and Jeremy, 2018 ; 2020 ; Browning et al., 2022 ).

Racial discrimination and segregation are also significant factors contributing to the inequitable distribution of park green spaces ( Wolch et al., 2014 ; Rigolon, 2016 ). Historically, due to the dominant position of white people, public facilities such as parks were predominantly located in affluent areas, while industrial zones and high-density housing were situated in areas inhabited by people of color and low-income individuals, a legacy that continues to have profound effects. Racial discrimination and segregation make it more difficult for communities of color to access park green spaces ( Dai, 2011 ), even when they reside closer to them. Issues such as smaller park areas, poor quality, and environmental pollution discourage residents from utilizing these spaces ( Alessandro and Jeremy, 2018 ), exacerbating the inequities in park green space distribution ( Wolch et al., 2013 ).

7 Prospects and challenges

7.1 opportunities for future research.

(1) Equity of Parks and Green Spaces for Different User Groups: Future research should focus on the fairness of park green space usage among different demographic groups, especially vulnerable populations such as the elderly ( Guo et al., 2019 ), children, and low-income individuals.

(2) Emerging Evaluation Methods and Data: Future studies can further integrate the latest information technologies, such as mobile signaling data ( Xiao et al., 2019 ; Heikinheimo et al., 2020 ), big data, Public Participation Geographic Information Systems (PPGIS) ( Brown et al., 2014 ), and the latest fairness evaluation criteria, such as the 3–30-300 rule ( Browning et al., 2024 ), to accurately simulate the diverse and complex transportation patterns and travel habits of urban residents. This approach will enable precise identification of the needs and behaviors of different population groups.

(3) Park green space equity based on perceived accessibility: Perceived accessibility refers to residents’ subjective perceptions and evaluations of the accessibility of park green spaces, emphasizing their perception and satisfaction with the level of accessibility ( Sugiyama et al., 2008 ; Mass et al., 2009 ). Studies have shown that actual spatial accessibility does not completely match perceived accessibility ( Wang et al., 2015 ; Crouse et al., 2017 ; Xie et al., 2018 ; Huang and Lin, 2023 ), especially in areas with low perceived accessibility within cities ( Crouse et al., 2017 ). This difference is mainly attributed to factors such as residents’ familiarity with the objective environment, the completeness of accessibility measurement methods, and individual differences among residents. Some scholars have studied perceived accessibility by comparing the time or distance required to reach destinations. For example, some studies have compared perceived distances to actual distances for several different destinations and found that destinations closer to home are often overestimated, meaning that the perceived distance is greater than the actual distance ( Wang et al., 2015 ). In the future, it is important to focus on the subjective perceptions of different groups and further refine research on park green space equity.

(4) Equity in park green space and Surface Temperature: In recent years, many regions globally have faced extreme high-temperature weather. Numerous studies have confirmed that parks and green spaces can effectively alleviate the urban heat island effect. Therefore, providing sufficient and equitable access to parks for residents is considered crucial for sustainable urban development. Scholars have already conducted relevant studies, such as in Dongguan, China, to explore whether the spatially equitable distribution of parks and green spaces contributes to mitigating the urban heat island effect and improving the urban thermal environment ( Chao et al., 2022 ). Other researchers have assessed the carbon reduction potential of 65 urban parks based on the cumulative outdoor carbon reduction model of park surface temperature reduction curves, conducting a network analysis of the spatial accessibility of cooling zones in Da Xi Park ( Du et al., 2023 ). Air temperature might be more salient, even if harder to implement. Future research should delve deeper into the specific relationship between parks and green spaces and surface temperature. For instance, investigating the scale of parks required within certain land areas to effectively reduce surface temperature, and exploring the intricate connection between the equitable distribution of parks and green spaces and surface temperature.

7.2 Limitations of the study

• This study has limitations regarding the selection of databases: The literature was derived from the WOS core database. The choice of databases may result in the omission of some relevant literature, posing a risk of literature gaps. Future research could consider expanding the scope of database selection, such as incorporating Scopus, PubMed, and others, to obtain a more comprehensive literature review.

• Due to the large sample size of the literature, specific quantitative analysis of the research results was not feasible. Subsequent studies may consider increasing the criteria for selecting literature to reduce the research sample, thereby making the analysis results more persuasive.

These limitations should be addressed and rectified in subsequent research to enhance the comprehensiveness and objectivity of the study. Additionally, a more detailed content analysis of relevant literature is warranted to gain a deeper understanding of the current status and trends in the field of equity in park green space.

8 Conclusion

To unveil the research focal points, developmental trends, and influencing mechanisms in the domain of equity in park green space, this study employed CiteSpace software to analyze research spanning from 2014 to December 2023. The key findings are summarized as follows:

(1) The investigation into equity in park green space has gained increasing prominence, delineated into two major phases: a gradual exploration phase (2014–2018) and a rapid development phase (2018 to the present). The primary nations engaged in this research arena include China, the United States, and Germany. Notably, China’s cumulative publication output is nearly three times that of the second-ranked United States (56) and over five times that of the third-ranked Germany (30). However, collaborative efforts with other nations remain limited.

(2) The current research in this field mainly focuses on three key areas: analysis of park green space equity based on primary social fairness, analysis of park green space equity focusing on vulnerable groups, and the relationship between park green spaces and health.

(3) The influencing factors of park green space equity mainly involve two major aspects: regional economy and government planning, and residents’ economic capability and racial discrimination.

(4) In the future, research can be directed towards several areas including park green space equity among different groups, emerging evaluation methods and data, park green space equity based on perceived accessibility, and the relationship between park green space equity and surface temperature.

In conclusion, this study presents novel insights and recommendations for advancing research on equity in park green space. The outcomes offer valuable references for global park green space planning and management, contributing theoretical support for the further development of equity-focused research in this domain.

Author contributions

LY: Funding acquisition, Methodology, Project administration, Writing–review and editing, Funding acquisition, Methodology, Project administration, Writing–review and editing. XJ: Data curation, Software, Writing–original draft, Data curation, Software, Writing–original draft. JZ: Writing–review and editing.

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This research was funded by Zhejiang Provincial Department of Education, grant number Y202146282.

Conflict of interest

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

Publisher’s note

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

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Keywords: park green space, equity, citespace, China, review

Citation: Yan L, Jin X and Zhang J (2024) Equity in park green spaces: a bibliometric analysis and systematic literature review from 2014-2023. Front. Environ. Sci. 12:1374973. doi: 10.3389/fenvs.2024.1374973

Received: 23 January 2024; Accepted: 07 March 2024; Published: 19 March 2024.

Reviewed by:

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

*Correspondence: Lijie Yan, [email protected]