The PRISMA 2020 reporting guideline for writing a systematic review and meta-analysis

The PRISMA 2020 reporting guideline helps authors write systematic reviews that can be understood and used by a wide audience. This page summarises PRISMA 2020 and how it can be used. Each guideline item links to more information, examples, and relevant training.

Journals endorsing PRISMA 2020 500+

PRISMA 2020: The Preferred Reporting Items for Systematic reviews and Meta-Analyses

Version: 1.1. This is the latest version ✅

How to use this reporting guideline

You can use reporting guidelines throughout your research process.

• When writing: Consider using a writing guide to draft your manuscript or protocol.
• After writing: Complete a checklist and include it with your journal submission.
• To learn: Consult the guidance whenever you need it.

However you use PRISMA 2020, please cite it.

Applicability criteria

You can use PRISMA 2020 if you are writing a systematic review of studies that evaluate the effects of health interventions, irrespective of the design of the included studies.

You can use this reporting guideline regardless of whether your systematic review included a synthesis (such as pairwise meta-analysis or other statistical synthesis methods) or not (for example, because only one eligible study is identified).

Many of the items are also applicable to:

• writing systematic reviews evaluating other kinds of interventions (such as social or educational interventions)
• systematic reviews with objectives other than evaluating interventions (such as evaluating aetiology, prevalence, or prognosis).

You can also use this reporting guideline to review the reporting of a systematic review, but not for appraising the quality of its design or conduct.

Do not use PRISMA 2020 for:

• writing a synthesis of observational research, use MOOSE instead.
• when writing a synthesis of purely qualitative studies, use ENTREQ instead.
• writing a meta-ethnography study, use eMERGe instead
• writing a proposal or protocol for a systematic review, use PRISMA-P instead.
• appraising the quality of a systematic review, use an appraisal tool like the CASP Checklist: Systematic Reviews with Meta-Analysis of Randomised Controlled Trials (RCTs)

There are several extensions which can be used in addition to PRISMA , these include:

• PRISMA Harms, for describing adverse events
• PRISMA Search, for describing systematic literature searches
• PRISMA for Network Meta-analyses

Other reporting guidelines for different types of systematic review should be used instead of PRISMA, including:

• PRISMA-Lsr for writing living systematic reviews
• PRISMA-Scr for writing systematic scoping reviews
• PRISMA-Dta for writing systematic reviews of diagnostic test accuracy studies
• PRISMA-Ipd for writing systematic reviews using individual participant data

Other extensions can be found here

For appraising research, consider using the CASP Systematic Reviews with Meta-Analysis of RCTs Checklist

Summary of guidance

Although you should describe all items below, you can decide how to order and prioritize items most relevant to your study, findings, context, and readership whilst keeping your writing concise. You can read how PRISMA 2020 was developed in the FAQs.

Item name	What to write
Title and Abstract
1. Title	Identify the report as a systematic review.
2. Abstract	Include all items from the PRISMA 2020 for Abstracts checklist.
Introduction
3. Rationale	Describe the rationale for the review in the context of existing knowledge.
4. Objectives	Provide an explicit statement of the objective(s) or question(s) the review addresses.
Methods
5. Eligibility criteria	Specify the inclusion and exclusion criteria for the review and how studies were grouped for the syntheses.
6. Information sources	Specify all databases, registers, websites, organisations, reference lists, and other sources searched or consulted to identify studies. Specify the date when each source was last searched or consulted Specify the date when each source (such as database, register, website, organisation) wa…
8. Search	Present the full search strategies for all databases, registers, and websites, including any filters and limits used Provide the full line by line search strategy as run in each database with a sophisticated interface (such as Ovid), or the sequence of terms that were used to search si…
8. Selection Process	Specify the methods used to decide whether a study met the inclusion criteria of the review, including how many reviewers screened each record and each report retrieved, whether they worked independently, and, if applicable, details of automation tools used in the process.
9. Data collection process	Specify the methods used to collect data from reports, including how many reviewers collected data from each report, whether they worked independently, any processes for obtaining or confirming data from study investigators, and, if applicable, details of automation tools used in the process R…
10. Data Items
10a. Outcomes	List and define all outcomes for which data were sought. Specify whether all results that were compatible with each outcome domain in each study were sought (for example, for all measures, time points, analyses), and, if not, the methods used to decide which results to collect. List and de…
10b. Other Variables	List and define all other variables for which data were sought (such as participant and intervention characteristics, funding sources). Describe any assumptions made about any missing or unclear information List and define all other variables for which data were sought. It may be sufficien…
11. Risk of bias in individual studies	Specify the methods used to assess risk of bias in the included studies, including details of the tool(s) used, how many reviewers assessed each study and whether they worked independently, and, if applicable, details of automation tools used in the process. Specify the tool(s) (and version) u…
12. Effect measures	Specify for each outcome the effect measure(s) (such as risk ratio, mean difference) used in the synthesis or presentation of results. Specify for each outcome or type of outcome (such as binary, continuous) the effect measure(s) (such as risk ratio, mean difference) used in the synthe…
13. Synthesis Methods
13a. Deciding which studies were eligible for each synthesis	Describe the processes used to decide which studies were eligible for each synthesis (such as tabulating the study intervention characteristics and comparing against the planned groups for each synthesis described in item 5.
13b. Data preparation methods	Describe any methods required to prepare the data for presentation or synthesis, such as handling of missing summary statistics or data conversions. Report any methods required to prepare the data collected from studies for presentation or synthesis, such as handling of missing summary…
13c. Methods for tabulating or displaying results	Describe any methods used to tabulate or visually display results of individual studies and syntheses Report chosen tabular structure(s) used to display results of individual studies and syntheses, along with details of the data presented. Report chosen graphical methods used to v…
13d. Synthesis methods	Describe any methods used to synthesise results and provide a rationale for the choice(s). If meta-analysis was performed, describe the model(s), method(s) to identify the presence and extent of statistical heterogeneity, and software package(s) used. If statistical synthesis methods were used…
13e. Methods for exploring heterogeneity	Describe any methods used to explore possible causes of heterogeneity among study results (such as subgroup analysis, meta-regression). If methods were used to explore possible causes of statistical heterogeneity, specify the method used (such as subgroup analysis, meta-regression). -…
13f. Sensitivitiy analyses	Describe any sensitivity analyses conducted to assess robustness of the synthesised results. If sensitivity analyses were performed, provide details of each analysis (such as removal of studies at high risk of bias, use of an alternative meta-analysis model). If any sensitivity an…
14. Reporting bias assessment	Describe any methods used to assess risk of bias due to missing results in a synthesis (arising from reporting biases) Specify the methods (tool, graphical, statistical, or other) used to assess the risk of bias due to missing results in a synthesis (arising from reporting biases). …
15. Certainty assessment	Describe any methods used to assess certainty (or confidence) in the body of evidence for an outcome Specify the tool or system (and version) used to assess certainty in the body of evidence. Report the factors considered (such as precision of the effect estimate, consistency of f…
Results
16. Study Selection
16a. Results of the search and selection process	Describe the results of the search and selection process, from the number of records identified in the search to the number of studies included in the review, ideally using a flow diagram
16b. Excluded studies	Cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why they were excluded. Cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why they were excluded.
17. Study characteristics	Cite each included study and present its characteristics. Cite each included study. Present the key characteristics of each study in a table or figure (considering a format that will facilitate comparison of characteristics across the studies).
18. Risk of bias in studies	Present assessments of risk of bias for each included study Present tables or figures indicating for each study the risk of bias in each domain/component/item assessed and overall study-level risk of bias. Present justification for each risk of bias judgment—for example, in t…
19. Results of individual studies	For all outcomes, present for each study (a) summary statistics for each group (where appropriate) and (b) an effect estimate and its precision (such as confidence/credible interval), ideally using structured tables or plots For all outcomes, irrespective of whether statistical synthesis w…
20. Results of Synthesis
20a. Summary of studies	For each synthesis, briefly summarise the characteristics and risk of bias among contributing studies. Provide a brief summary of the characteristics and risk of bias among studies contributing to each synthesis (meta-analysis or other). The summary should focus only on study character…
20b. Statistical results	Present results of all statistical syntheses conducted. If meta-analysis was done, present for each the summary estimate and its precision (such as confidence/credible interval) and measures of statistical heterogeneity. If comparing groups, describe the direction of the effect. Report results…
20c. Heterogeneity	Present results of all investigations of possible causes of heterogeneity among study results. If investigations of possible causes of heterogeneity were conducted: present results regardless of the statistical significance, magnitude, or direction of effect modification. …
20d. Sensitivity analyses	Present results of all sensitivity analyses conducted to assess the robustness of the synthesised results If any sensitivity analyses were conducted: report the results for each sensitivity analysis. comment on how robust the main analysis was given the results of all…
21. Risk of reporting biases in syntheses	Present assessments of risk of bias due to missing results (arising from reporting biases) for each synthesis assessed Present assessments of risk of bias due to missing results (arising from reporting biases) for each synthesis assessed. If a tool was used to assess risk of bias due …
22. Certainty of evidence	Present assessments of certainty (or confidence) in the body of evidence for each outcome assessed Report the overall level of certainty in the body of evidence (such as high, moderate, low, or very low) for each important outcome. Provide an explanation of reasons for rating down (or…
Discussion
23. Discussion
23a. General interpretation of the results	Provide a general interpretation of the results in the context of other evidence Provide a general interpretation of the results in the context of other evidence.
23b. Limitations of included evidence	Discuss any limitations of the evidence included in the review Discuss any limitations of the evidence included in the review.
23c. Limitations of the review processes	Discuss any limitations of the review processes used Discuss any limitations of the review processes used and comment on the potential impact of each limitation.
23d. Implications	Discuss implications of the results for practice, policy, and future research Discuss implications of the results for practice and policy. Make explicit recommendations for future research.
Other Information
24. Registration and Protocol
24a. Registration	Provide registration information for the review, including register name and registration number, or state that the review was not registered Provide registration information for the review, including register name and registration number, or state that the review was not registered.
24b. Protocol	Indicate where the review protocol can be accessed, or state that a protocol was not prepared Indicate where the review protocol can be accessed (such as by providing a citation, DOI, or link) or state that a protocol was not prepared.
24c. Amendments	Describe and explain any amendments to information provided at registration or in the protocol Report details of any amendments to information provided at registration or in the protocol, noting: (a) the amendment itself, (b) the reason for the amendment, and (c) the stage of the…
25. Support	Describe sources of financial or non-financial support for the review, and the role of the funders or sponsors in the review Describe sources of financial or non-financial support for the review, specifying relevant grant ID numbers for each funder. If no specific financial or non-fina…
26. Competing Interests	Declare any competing interests of review authors Disclose any of the authors’ relationships or activities that readers could consider pertinent or to have influenced the review. If any authors had competing interests, report how they were managed for particular review processes.
27. Availability of data, code, and other materials	Report which of the following are publicly available and where they can be found: template data collection forms; data extracted from included studies; data used for all analyses; analytic code; any other materials used in the review Report which of the following are publicly available: templa…

We like publishing transparent research because we think it’s more likely to be used and cited. That’s why we ask authors to use reporting guidelines.

Robin Lavery

Editor, International Journal of World Medicine

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Systematic_review

A review that uses explicit, systematic methods to collate and synthesize findings of studies that address a clearly formulated question.

Source

Statistical synthesis

The combination of quantitative results of two or more studies. This encompasses meta-analysis of effect estimates (described below) and other methods, such as combining P values, calculating the range and distribution of observed effects, and vote counting based on the direction of effect (see McKenzie and Brennan for a description of each method)

Meta-analysis of effect estimates

A statistical technique used to synthesize results when study effect estimates and their variances are available, yielding a quantitative summary of results.

Source

Outcome

An event or measurement collected for participants in a study (such as quality of life, mortality).

Result

The combination of a point estimate (such as a mean difference, risk ratio or proportion) and a measure of its precision (such as a confidence/credible interval) for a particular outcome.

Reports

Documents (paper or electronic) supplying information about a particular study. A report could be a journal article, preprint, conference abstract, study register entry, clinical study report, dissertation, unpublished manuscript, government report, or any other document providing relevant information.

Record

The title or abstract (or both) of a report indexed in a database or website (such as a title or abstract for an article indexed in Medline). Records that refer to the same report (such as the same journal article) are “duplicates”; however, records that refer to reports that are merely similar (such as a similar abstract submitted to two different conferences) should be considered unique.

Study

An investigation, such as a clinical trial, that includes a defined group of participants and one or more interventions and outcomes. A “study” might have multiple reports. For example, reports could include the protocol, statistical analysis plan, baseline characteristics, results for the primary outcome, results for harms, results for secondary outcomes, and results for additional mediator and moderator analyses.