The PRISMA 2020 statement is the updated version of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), replacing the original 2009 guidelines that had been cited over 60,000 times. Published by Page et al. in 2021, PRISMA 2020 introduces a revised 27-item checklist, four new flow diagram templates, and expanded guidance designed to improve transparency, completeness, and reproducibility in systematic review reporting.
If you are conducting or reporting a systematic review today, understanding the differences between PRISMA 2020 and the original PRISMA statement is essential for meeting current journal requirements and ensuring your review meets evidence synthesis standards.
What Was the Original PRISMA Statement?
The original PRISMA statement, published in 2009 by Moher et al., established a 27-item checklist and a single flow diagram template for reporting systematic reviews and meta-analyses. It replaced the earlier QUOROM statement (1999) and became the most widely used reporting guideline in evidence-based research.
The 2009 PRISMA checklist covered key reporting elements across the title, abstract, methods, results, and discussion sections of a systematic review. Its flow diagram provided a standardized way to visualize the study selection process, tracking records from identification through screening to final inclusion.
However, after over a decade of use, several limitations became apparent. The original statement did not distinguish between different types of sources, lacked guidance for updated reviews, and some checklist items needed clarification or expansion based on advances in systematic review methodology.
The 7 Key Changes in PRISMA 2020
1. Revised and Expanded Checklist
The PRISMA 2020 checklist retains 27 items but substantially revises their content. Many items have been split into sub-items for greater specificity. For example, the methods section now requires separate reporting of eligibility criteria, information sources, search strategy, selection process, data collection, study risk of bias assessment, effect measures, synthesis methods, and reporting bias assessment. Read our detailed breakdown of the 27-item PRISMA 2020 checklist.
2. Four New Flow Diagram Templates
Perhaps the most visible change is the replacement of the single flow diagram with four distinct templates. PRISMA 2020 now distinguishes between new and updated systematic reviews, and between reviews that searched only databases/registers versus those that also used other sources such as citation searching, grey literature, or organizational websites. Learn which template applies to your review in our guide to the four official PRISMA 2020 flow diagram templates.
3. Distinction Between Records, Reports, and Studies
PRISMA 2020 explicitly differentiates between records (database entries returned by a search), reports (full-text documents), and studies (research investigations, which may produce multiple reports). This three-level distinction provides a more accurate representation of the study selection process.
4. Records Removed Before Screening
The updated flow diagram includes a dedicated box for records removed before screening, broken down into duplicate records, records marked as ineligible by automation tools, and records removed for other reasons. This reflects the growing use of deduplication software and machine learning tools in systematic review workflows.
5. Enhanced Reporting of Search Methods
PRISMA 2020 places greater emphasis on transparent search reporting, including the requirement to present full search strategies for all databases. This aligns with the PRISMA-S extension for search reporting. For detailed guidance on search documentation, see our article on how to report search strategies using PRISMA-S.
6. Risk of Bias and Certainty Assessments
The updated statement adds explicit requirements for reporting risk of bias assessments at the individual study level and across the body of evidence. It also incorporates certainty assessments (such as GRADE), reflecting the evolution of evidence synthesis methodology.
7. Guidance for Updated Reviews
For the first time, PRISMA provides dedicated templates and guidance for updated systematic reviews. These templates include fields for studies and reports from the previous version of the review, allowing readers to distinguish between previously identified and newly identified evidence.
Impact on Systematic Review Reporting
The transition to PRISMA 2020 has significant implications for researchers conducting systematic reviews:
- Journal requirements: Most peer-reviewed journals now expect PRISMA 2020 compliance for systematic review submissions. Using the outdated 2009 format may result in desk rejection or revision requests.
- Review registration: Protocols registered on PROSPERO should align with PRISMA 2020 reporting expectations.
- Software and tools: Many systematic review management tools, including our free PRISMA 2020 flow diagram generator, have updated to support the new templates.
- Teaching and training: Research methodology courses and textbooks are being updated to reflect the PRISMA 2020 standards.
Side-by-Side Comparison
| Feature | PRISMA 2009 | PRISMA 2020 |
|---|---|---|
| Checklist items | 27 | 27 (substantially revised) |
| Flow diagram templates | 1 | 4 |
| Records/reports/studies | Not distinguished | Explicitly distinguished |
| Updated review support | No | Yes, with dedicated templates |
| Pre-screening removal | Not included | Duplicates, automation, other |
| Other sources column | Not included | Included in 2 templates |
| Risk of bias reporting | Minimal | Expanded requirements |
| Search strategy detail | Limited | Enhanced (PRISMA-S alignment) |
| Certainty assessment | Not required | Recommended (GRADE) |
| Automation tools | Not addressed | Acknowledged in flow diagram |
How to Transition from PRISMA 2009 to PRISMA 2020
If you are updating a systematic review originally reported using PRISMA 2009, or if you are writing a new review and are familiar with the older format:
- Download the PRISMA 2020 checklist from the official PRISMA website and compare it item-by-item with your current reporting.
- Select the appropriate flow diagram template based on your review type and sources used.
- Use a compliant tool such as our PRISMA flow diagram generator tool to create your updated flow diagram with the correct template.
- Review the explanation and elaboration document published alongside the PRISMA 2020 statement for detailed guidance on each checklist item.
Frequently Asked Questions
Is PRISMA 2020 mandatory for all systematic reviews?
PRISMA 2020 is not legally mandatory, but it is the expected reporting standard for systematic reviews submitted to peer-reviewed journals. Most major journals endorse or require PRISMA compliance, and reviewers increasingly check for PRISMA 2020 adherence during peer review.
Can I still use the original PRISMA 2009 flow diagram?
While not prohibited, using the 2009 flow diagram is strongly discouraged. It does not capture the level of detail expected by PRISMA 2020, such as the distinction between databases and other sources, pre-screening record removal, or separate reporting of records, reports, and studies.
Do I need to use all 4 PRISMA 2020 templates?
No. You only use one template per systematic review, selected based on whether your review is new or updated and whether you searched databases only or also used other sources. Most reviews use either template 1 (new, databases only) or template 2 (new, databases + other sources).
Where can I create a PRISMA 2020 flow diagram?
You can use our free PRISMA diagram tool to create professional, publication-ready flow diagrams that support all four template types with live preview and instant PNG download.