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 to use it.

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: consult the full guidance when writing manuscripts, protocols, and applications. The summary below provides a useful overview, and each item links to fuller guidance with explanations and examples.
• After writing: Complete a checklist and include it with your journal submission.
• To learn: Use PRISMA 2020 and our training to develop as an academic and build writing skills.

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.
7. Search	Present the full search strategies for all databases, registers and websites, including any filters and limits used.
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.
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 (e.g. for all measures, time points, analyses), and if not, the methods used to decide which results to collect.
10b. Other Variables	List and define all other variables for which data were sought (e.g. participant and intervention characteristics, funding sources). Describe any assumptions made about any missing or unclear information.
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.
12. Effect measures	Specify for each outcome the effect measure(s) (e.g. risk ratio, mean difference) used in the synthesis or presentation of results.
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 (e.g. tabulating the study intervention characteristics and comparing against the planned groups for each synthesis (item
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.
13c. Methods for tabulating or displaying results	Describe any methods used to tabulate or visually display results of individual studies and syntheses.
13d. Synthesis methods	Describe any methods used to synthesize 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.
13e. Methods for exploring heterogeneity	Describe any methods used to explore possible causes of heterogeneity among study results (e.g. subgroup analysis, meta-regression).
13f. Sensitivity analyses	Describe any sensitivity analyses conducted to assess robustness of the synthesized results.
14. Reporting bias assessment	Describe any methods used to assess 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.
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.
17. Study characteristics	Cite each included study and present its characteristics.
18. Risk of bias in studies	Present assessments of risk of bias for each included study.
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 (e.g. confidence/credible interval), ideally using structured tables or plots.
20. Results of Synthesis
20a. Summary of studies	For each synthesis, briefly summarise the characteristics and risk of bias among contributing studies.
20b. Statistical results	Present results of all statistical syntheses conducted. If meta-analysis was done, present for each the summary estimate and its precision (e.g. confidence/credible interval) and measures of statistical heterogeneity. If comparing groups, describe the direction of the effect.
20c. Heterogeneity	Present results of all investigations of possible causes of heterogeneity among study results.
20d. Sensitivity analyses	Present results of all sensitivity analyses conducted to assess the robustness of the synthesized results.
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.
22. Certainty of evidence	Present assessments of certainty (or confidence) in the body of evidence for each outcome assessed.
Discussion
23. Discussion
23a. General interpretation of the results	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.
23c. Limitations of the review processes	Discuss any limitations of the review processes used.
23d. Implications	Discuss implications of the results for practice, policy, and 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.
24b. Protocol	Indicate where the review protocol can be accessed, or state that a protocol was not prepared.
24c. Amendments	Describe and explain any amendments to information provided at registration or in the protocol.
25. Support	Describe sources of financial or non-financial support for the review, and the role of the funders or sponsors in the review.
26. Competing Interests	Declare any competing interests of review authors.
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.

Including the appropriate EQUATOR checklist as part of your submission goes a long way to help establish trust between authors, editors, and reviewers. That’s why our editorial team ensures that applicable reporting checklists are completed during the peer review process, with a completed checklist at submission greatly helping editors and peer reviewers to assess the work.

Adrian Aldcroft

Editor in Chief, BMJ Open

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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.