PRISMA Flow Diagrams

What is a PRISMA Diagram?

The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram is a visual representation of the study selection process. It shows how many studies were identified, screened, excluded (with reasons), and ultimately included in your systematic review.

Why PRISMA Diagrams are Required

  • Required by most journals for systematic review publication
  • Ensures transparency and reproducibility
  • Shows comprehensive search strategy
  • Documents reasons for exclusion at each stage
  • Allows readers to assess review rigor
  • PRISMA 2020 updated guidelines are current standard

PRISMA Diagram Structure

Identification Phase

  • Records identified from database searches
  • Records identified from other sources (registers, citations, etc.)
  • Records removed before screening (duplicates, marked as ineligible)
  • Records screened (title/abstract)

Screening Phase

  • Records excluded at abstract screening
  • Reports sought for retrieval
  • Reports not retrieved (unobtainable)
  • Reports assessed for eligibility (full-text)

Inclusion Phase

  • Reports excluded at full-text (with reasons)
  • Studies included in review
  • Studies included in meta-analysis (if subset)

Generating PRISMA Diagram in Scholara

  1. 1Complete all screening phases (abstract and full-text)
  2. 2In the Analysis Chat, ask the AI to generate a PRISMA diagram (e.g., 'Generate a PRISMA 2020 flow diagram for this review')
  3. 3Scholara automatically counts records at each stage from your screening data
  4. 4The diagram appears as an interactive asset in the chat
  5. 5Ask for customizations in follow-up messages if needed
  6. 6Export in your preferred format using the export menu on the asset card

Automatic Calculations

Scholara automatically tracks and calculates:

  • Total records from your database searches
  • Records from other sources (manually added studies)
  • Duplicates removed (automatic deduplication across databases)
  • Records excluded at abstract screening
  • Full-texts retrieved and assessed
  • Full-texts excluded with reasons
  • Final included studies
  • Studies in meta-analysis (if applicable)

Exclusion Reasons

PRISMA 2020 requires reporting primary exclusion reasons. Scholara tracks:

  • Wrong population/participants
  • Wrong intervention/exposure
  • Wrong comparator/control
  • Wrong outcomes measured
  • Wrong study design
  • Wrong publication type (editorial, commentary)
  • Insufficient data reported
  • Duplicate/secondary publication

Each excluded study should have one primary reason. If multiple reasons apply, choose the most fundamental one.

PRISMA 2020 vs Original PRISMA

Key differences in PRISMA 2020:

  • Separates database and register searches
  • Includes identification through website screening and organizations
  • More detailed reporting of exclusion reasons
  • Distinguishes reports vs studies (one study may have multiple reports)
  • Scholara defaults to PRISMA 2020 format
  • Original PRISMA format available if journal requires

Customizing Your Diagram

Layout Options

  • Vertical (standard) or horizontal orientation
  • Color scheme (grayscale for print, color for presentations)
  • Box sizes and spacing
  • Font sizes and styles
  • Include/exclude optional elements

Content Customization

  • Add notes for specific stages (e.g., search date ranges)
  • Specify database names
  • List exclusion reasons with counts
  • Include/exclude certain sources
  • Add institution/review branding

Exporting PRISMA Diagrams

Export Formats

  • PNG: High-resolution raster (300+ DPI for publication)
  • PDF: Vector format, scalable
  • SVG: Editable vector format
  • Word .docx: Editable in Microsoft Word
  • PowerPoint: For presentations

Publication Quality

  • 300 DPI minimum for journal submission
  • Check journal requirements (format, dimensions)
  • Ensure text is readable at print size
  • Grayscale often preferred over color
  • Include as Figure 1 in most systematic reviews

Common Issues and Solutions

Numbers Don't Add Up

If totals seem incorrect:

  1. 1Check for studies with incomplete screening
  2. 2Verify all duplicates were marked
  3. 3Confirm all exclusion reasons assigned
  4. 4Review studies marked as 'Uncertain' (should be resolved)
  5. 5Check for any imports or additions after initial screening
  6. 6Regenerate diagram after corrections

Multiple Reports from Same Study

PRISMA 2020 distinguishes reports from studies:

  • Link multiple reports to same study in Scholara
  • Diagram shows 'reports' until final stage
  • Final box shows 'studies included in review'
  • Example: 50 reports may represent 45 unique studies
  • This is important for meta-analysis (don't double-count data)

PRISMA for Different Review Types

Scoping Reviews

Use PRISMA-ScR (Scoping Review extension):

  • Similar structure but less emphasis on quality assessment
  • May include broader range of study designs
  • Scholara provides PRISMA-ScR template

Network Meta-Analysis

Use PRISMA-NMA extension:

  • Includes network diagram showing intervention comparisons
  • Additional reporting for geometry of network
  • Scholara generates both flow diagram and network diagram

Beyond the Flow Diagram

PRISMA includes more than just the flow diagram:

  • 27-item checklist for reporting
  • Abstract structured summary
  • Methods transparency
  • Bias assessment reporting
  • Certainty of evidence assessment

Checklist Generation

Scholara can generate a PRISMA checklist:

  1. 1Ask the Analysis Chat to generate a PRISMA checklist (e.g., 'Generate a PRISMA 2020 checklist for this review')
  2. 2The AI auto-fills items based on your review data
  3. 3Review each item and add page numbers
  4. 4Export as needed for manuscript submission
  5. 5Most journals require both diagram and checklist

The PRISMA flow diagram is often the first figure readers see in your systematic review. Take time to ensure numbers are accurate and presentation is clear. Any discrepancies will raise questions about review rigor.