PRISMA 2020 Guidelines: What Researchers Need to Know for Publication Success

The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement is the gold standard for reporting systematic reviews. The 2020 update brought significant changes that all researchers conducting systematic reviews need to understand. Following these guidelines is not just about compliance - it's about producing high-quality, transparent research that can be trusted.

Having led over 100 systematic reviews and served as a Cochrane Review author, I've seen how proper PRISMA compliance can make the difference between publication acceptance and rejection. In this guide, I'll walk you through the key requirements and share practical strategies for implementation.

Understanding PRISMA 2020

PRISMA 2020 represents a major update to the original 2009 statement. The revision reflects advances in systematic review methodology, the growth of different review types, and lessons learned from thousands of published reviews. The updated statement includes 27 checklist items and a revised flow diagram.

The changes aren't just cosmetic - they reflect a deeper commitment to transparency, reproducibility, and methodological rigor in evidence synthesis. Understanding these changes is essential for anyone planning to publish a systematic review in a peer-reviewed journal.

Key Changes in PRISMA 2020

New Reporting Items

PRISMA 2020 introduced several new items that weren't explicitly required in the 2009 version. These additions address gaps identified through years of review experience and methodological research.

• Registration and protocol information (where registered, protocol availability)
• Methods for assessing risk of bias in included studies
• Methods for assessing certainty of evidence (GRADE approach)
• Description of any deviations from the registered protocol
• Reporting of automation tools used in the review process

Enhanced Flow Diagram

The updated flow diagram template now provides a more comprehensive picture of the study selection process. The new format better captures the complexity of modern systematic reviews.

• Separate tracking of studies from different database sources
• Explicit accounting for gray literature and other sources
• Clear documentation of automation tool usage
• Accommodation for updated searches in living reviews
• Reasons for exclusion at full-text review stage

Structured Abstract Checklist

PRISMA 2020 includes a dedicated 12-item checklist specifically for abstracts. Given that many readers only see the abstract, ensuring it comprehensively summarizes the review is critical.

Implementing PRISMA in Your Review

Step 1: Protocol Registration

Before starting your review, register your protocol in PROSPERO or another appropriate registry. This step is now expected by most journals and demonstrates commitment to transparency.

• Defines your methods before you see the results
• Reduces potential for selective reporting
• Increases transparency and reproducibility
• Required by many high-impact journals
• Provides a citeable record of your planned methods

Step 2: Comprehensive Search Strategy

Your search strategy is the foundation of your review. PRISMA 2020 requires detailed documentation of all searches conducted. Work with a librarian or information specialist if possible.

• Document all databases searched (at minimum: MEDLINE, Embase, CENTRAL)
• Provide complete search strategies for each database
• Record date ranges and any limits applied
• Include gray literature sources consulted
• Document any hand-searching or citation tracking

Step 3: Study Selection Process

PRISMA 2020 emphasizes transparency in how studies were selected. The process should be systematic, reproducible, and well-documented.

• Use dual independent screening for all stages
• Apply pre-defined eligibility criteria consistently
• Document clear reasons for exclusion at full-text stage
• Establish conflict resolution procedures before starting
• Consider using systematic review software for documentation

Step 4: Data Extraction

Systematic data extraction is essential for both accuracy and reproducibility. PRISMA 2020 requires clear documentation of your extraction process.

• Develop and pilot standardized extraction forms
• Use dual extraction with verification for key outcomes
• Document any contact with study authors for missing data
• Describe how missing data was handled
• Report any data conversions or calculations performed

Step 5: Risk of Bias Assessment

Critical appraisal of included studies is a cornerstone of systematic reviews. PRISMA 2020 requires clear reporting of risk of bias methods and results.

• Use Cochrane RoB 2 tool for randomized controlled trials
• Use ROBINS-I for non-randomized studies of interventions
• Use QUADAS-2 for diagnostic accuracy studies
• Conduct assessment independently by two reviewers
• Document all domain-level and overall judgments

Step 6: Data Synthesis

Whether you conduct a meta-analysis or narrative synthesis, clear reporting of your synthesis methods is required. PRISMA 2020 includes detailed guidance for both approaches.

• Describe statistical methods for meta-analysis clearly
• Report heterogeneity assessment methods and results
• Pre-specify subgroup and sensitivity analyses
• Assess and report on publication bias
• Consider certainty of evidence assessment (GRADE)

Common PRISMA Compliance Issues

Based on our experience reviewing and editing hundreds of systematic reviews, here are the most common compliance issues we see - and how to avoid them.

• Incomplete search strategy reporting (provide full strategies for all databases)
• Missing or incomplete PRISMA flow diagram (use the official template)
• Inadequate risk of bias assessment (use appropriate validated tools)
• No protocol registration (register in PROSPERO before conducting searches)
• Incomplete data extraction forms (provide as supplementary material)
• Missing PRISMA checklist (submit completed checklist with manuscript)

Conclusion

Following PRISMA 2020 guidelines improves the quality, transparency, and reproducibility of systematic reviews. Beyond compliance, these guidelines represent best practices that make your research more valuable and trustworthy.

Implementing PRISMA properly requires careful planning from the start of your review. By understanding the requirements and building them into your workflow, you can produce systematic reviews that meet the highest standards of evidence synthesis methodology.