What is PRISMA?
PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is the most widely used reporting guideline for systematic reviews. First published in 2009, the updated PRISMA 2020 statement was released in March 2021 to reflect advances in systematic review methodology.
Key Changes in PRISMA 2020
While the checklist retains 27 items, many have been substantially revised or expanded:
- Abstract: Now requires a structured abstract following the PRISMA for Abstracts checklist
- Protocol registration: Must report where the protocol was registered and provide the registration ID
- Eligibility criteria: Requires separate reporting of inclusion and exclusion criteria
- Search strategy: Must present the full search strategy for ALL databases, not just one
- Automation tools: Must disclose any automation tools used in the review process (e.g., machine learning for screening)
- Study risk of bias: Must specify the tool used and present results for each domain
- Certainty assessment: GRADE or equivalent certainty assessment is now a required reporting item
- Data availability: Authors should state whether data and analytic code are available
The Updated Flow Diagram
The PRISMA 2020 flow diagram has been significantly redesigned. Key additions include separate boxes for records identified from databases vs. other sources (registers, websites, citation searching), a new section for reports assessed for retrieval (before full-text), and clearer tracking of records through each phase. Templates are available on the PRISMA website (prisma-statement.org) in editable formats.
Common Compliance Mistakes
- Using the old 2009 flow diagram instead of the 2020 version
- Not reporting the full search strategy for every database searched
- Omitting the certainty of evidence assessment (GRADE)
- Not reporting protocol deviations
- Incomplete risk of bias reporting (just overall judgment without domain-level detail)
- Not disclosing conflicts of interest and funding sources
How to Comply
Download the PRISMA 2020 checklist and fill it in as you write your manuscript. Include page numbers for each item. Many journals now require the completed checklist as a supplementary file during submission. Using the checklist from the start of your review process — not just at the writing stage — ensures nothing is missed.
