PRISMA 2020 Explained: The Checklist, Flow Diagram & Guidelines
PRISMA 2020 is the reporting guideline that every systematic review and meta-analysis is now measured against. But unlike a simple style guide, PRISMA 2020 is a full package: a 27-item checklist, a standard flow diagram, and an explanation-and-elaboration document that together show what “open reporting” really means when you pull evidence together.
This guide explains exactly what PRISMA 2020 is, what changed from the original 2009 statement, and how the checklist and flow diagram are set up. It also shows how to actually use them — in practice, item by item — while you draft your manuscript. If you are looking for the step-by-step process of conducting the review itself, see our companion guide on how to conduct a PRISMA systematic review.
What Is PRISMA 2020?
PRISMA stands for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. It is not a method on its own — it does not tell you how to search, screen, or analyse your data. Instead, it is a reporting standard: a checklist that tells you what information your published manuscript must openly share so that readers, reviewers, and future researchers can judge and repeat your work.
The PRISMA 2020 statement came out at the same time in The BMJ, PLOS Medicine, and the Journal of Clinical Epidemiology, replacing the original 2009 PRISMA statement. It has three main parts: the 27-item checklist, the flow diagram template, and a detailed explanation-and-elaboration paper that spells out the point of each item.
PRISMA 2020 reports your method — it does not replace it. A poorly run review cannot be saved by good PRISMA reporting, but a well-run review can still be rejected for failing to report it properly.
Why PRISMA 2020 Replaced the 2009 Statement
Systematic review methodology evolved substantially between 2009 and 2020. New risk-of-bias tools, network meta-analysis, automation software, and a much stronger emphasis on evidence certainty made the original checklist outdated. The 2020 update addressed these gaps directly.
What Changed From PRISMA 2009 to PRISMA 2020
- Protocol registration and PROSPERO disclosure became explicit, named checklist items
- Search reporting now requires all databases, registers, and grey literature sources, plus the full search strategy for at least one database
- Risk of bias must be checked and reported at the outcome level, not just the study level
- Separate, more detailed guidance was added for reporting network meta-analyses
- The flow diagram was changed to separately track new versus updated searches
- Certainty of evidence (GRADE) is now a clear reporting requirement, expected in both the abstract and the results
The PRISMA 2020 27-Item Checklist
The checklist is grouped into sections that match the structure of a manuscript, making it easy to work through while drafting instead of fixing compliance at the end. The main sections are:
- Title & Abstract — identify the report as a systematic review and summarise key methodological details and findings
- Introduction — rationale and explicit objectives framed using PICO or an equivalent structured question
- Methods — eligibility criteria, information sources, search strategy, selection process, data collection, risk of bias assessment, effect measures, synthesis methods, and certainty assessment
- Results — study selection (with flow diagram), study characteristics, risk of bias results, individual and synthesised results, and certainty of evidence
- Discussion — interpretation of results in the context of other evidence, limitations, and implications
- Other Information — registration and protocol, support/funding, competing interests, and data availability
Each of the 27 items is deliberately specific — for example, item 9 asks you to describe the methods used to check risk of bias, while item 13f asks you to report certainty of evidence for each outcome. Vague or partial reporting on an item counts the same as leaving it out entirely.
Alongside the checklist itself, the PRISMA 2020 Explanation and Elaboration paper gives a worked reason for every single item — including example text pulled from published, well-reported reviews. Authors who check this companion document while drafting tend to write far stronger Methods and Results sections. Each checklist item comes with a clear example of what good reporting actually looks like, instead of a one-line instruction that is easy to get wrong.
The PRISMA 2020 Flow Diagram
The flow diagram is the single most recognisable part of any PRISMA-compliant systematic review. It shows, stage by stage, exactly how many records were found, screened, excluded, and finally included — with reasons for exclusion recorded at the full-text stage.
Identification
Total records identified from databases and registers, plus records identified through other methods such as citation searching, before any duplicates are removed.
Screening
Records remaining after duplicate removal, screened by title and abstract, with the number excluded at this stage clearly reported.
Eligibility
Full-text reports checked for eligibility, with every excluded report sorted by a specific, named reason — not a generic “did not meet criteria.”
Included
Studies included in the final review, and — separately — studies included in any statistical pooling (meta-analysis), since these two numbers are not always the same.
The 2020 version of the diagram also introduced an optional second template specifically for reviews that include an updated search. This lets authors distinguish new records found in an update from the original search results.
How to Use PRISMA 2020 When Writing Your Manuscript
The best way to use PRISMA 2020 is not as a final check at the end, but as a drafting scaffold from day one. Here is the approach we use in our own medical writing services:
- Download the current PRISMA 2020 checklist and flow diagram templates before drafting begins
- Map each of the 27 items to a specific planned section or paragraph of the manuscript
- Fill in the flow diagram numbers directly from your screening software (Rayyan, Covidence) as screening goes, not after the fact
- Write the abstract last, ensuring it includes GRADE certainty ratings as PRISMA 2020 requires
- Submit the completed checklist — with page numbers for each item — as a supplementary file alongside your manuscript
- Cross-check the final manuscript against the checklist one more time immediately before submission
Common PRISMA 2020 Compliance Mistakes
These are the most frequent PRISMA 2020 reporting errors we see when reviewing manuscripts that were rejected or sent back for major changes:
- Using the outdated 2009 flow diagram template instead of the current 2020 version
- Reporting risk of bias only at the study level, not the outcome level
- Submitting a checklist with item numbers ticked off but no corresponding page references
- Omitting GRADE certainty ratings from the abstract
- Failing to list all information sources, including grey literature and trial registers
- Reporting exclusion reasons at full-text stage as a single combined number instead of by category
Many journals now use PRISMA 2020 compliance as a desk-review gate — your manuscript may never reach a peer reviewer’s desk if the checklist is incomplete or the flow diagram uses the outdated 2009 template.
Frequently Asked Questions
Q. What is PRISMA 2020?
PRISMA 2020 is the current reporting guideline for systematic reviews and meta-analyses, published in 2020 to replace the original 2009 PRISMA statement. It has a 27-item checklist, a standard flow diagram, and an explanation-and-elaboration document.
Q. Is PRISMA 2020 a methodology or a reporting guideline?
PRISMA 2020 is a reporting guideline, not a method. It does not tell you how to search, screen, or analyse data — it sets out what information must be openly reported once those method decisions have been made.
Q. What are the main sections of the PRISMA 2020 checklist?
The 27 items are organised under Title and Abstract, Introduction, Methods, Results, Discussion, and Other Information (registration, funding, competing interests, and data availability).
Q. What is the PRISMA 2020 flow diagram used for?
The flow diagram shows the number of records found, screened, checked for eligibility, and included at each stage of the review, along with sorted reasons for exclusion at the full-text stage.
Q. Do journals require the PRISMA 2020 checklist to be submitted?
Most major journals require authors to submit a completed PRISMA 2020 checklist, with page or paragraph references for each item, as a supplementary file alongside the manuscript.
Q. Can I get professional help with PRISMA 2020 reporting?
Yes. I provide systematic review and medical writing services that build PRISMA 2020 compliance into the manuscript from the first draft, including full checklist and flow diagram preparation. Contact me for a free consultation.
Need Your Manuscript Written to Full PRISMA 2020 Compliance?
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