What is a PRISMA flow diagram?
Updated 2026-09-24
A PRISMA flow diagram is a standard chart that shows how many records a systematic review found, screened, excluded and finally included. It is the visual summary of your study selection process.
The short definition
PRISMA stands for Preferred Reporting Items for Systematic reviews and Meta-Analyses. The PRISMA flow diagram is the figure that reports the journey of every record in your review, from the first database search to the studies you analysed. Readers can see at a glance how large the search was, how many duplicates were removed, how many reports were read in full and why studies were excluded.
What the diagram shows
A PRISMA 2020 flow diagram is organised in three bands:
- Identification: records found in databases and registers (and through other methods such as websites or citation searching), and records removed before screening, such as duplicates.
- Screening: records screened by title and abstract, records excluded, reports sought for retrieval, reports that could not be retrieved, reports assessed for eligibility and reports excluded with reasons.
- Included: the final number of studies and reports included in the review.
Why the PRISMA flow diagram is important
It makes your review transparent and reproducible. A reviewer can check that your numbers add up, and other researchers can see whether your search was broad enough to trust. Most journals that publish systematic reviews expect it, and it supports item 16a of the PRISMA 2020 checklist, which asks you to describe the search and selection results, ideally using a flow diagram.
PRISMA 2009 vs PRISMA 2020
The 2009 diagram had four stages: Identification, Screening, Eligibility and Included. The PRISMA 2020 flow diagram keeps the idea but separates databases and registers from other methods, distinguishes records from reports, and offers a version for updated reviews. If you are starting a new review, use the 2020 version.
Where it goes in your paper
The diagram is normally Figure 1 and is cited in the Results section, in the paragraph that describes study selection. Add a short sentence with the key numbers, then refer readers to the figure for the full detail.
Next steps
Ready to draw yours? Read how to make a PRISMA flow diagram, look at a worked example, or open the free PRISMA flow diagram generator and start filling in your numbers.
Quick answers
What does PRISMA stand for?
PRISMA stands for Preferred Reporting Items for Systematic reviews and Meta-Analyses.
Is a PRISMA flow diagram required?
The PRISMA 2020 checklist recommends a flow diagram for reporting study selection, and most journals publishing systematic reviews expect one.
Source of the flow diagram wording: Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. doi:10.1136/bmj.n71. Licensed CC BY 4.0. This site is independent and not affiliated with the PRISMA or EQUATOR Network groups.