The PRISMA Flow Diagram:Count From Day One, Don't Draw It at the End

The PRISMA flow diagram shows how many records entered at the search stage, how many were removed at each step, and how many studies remained at the end.

Readers and reviewers use it to gauge the transparency of your review at a glance. A diagram whose numbers don't connect undermines the credibility of the whole review — which is exactly why it deserves care.

The general flow: records identified per database → records after deduplication → records screened at title/abstract, with the number excluded → reports assessed at full text, with exclusions broken down by reason → studies included.

The exact box structure depends on the version, such as PRISMA 2020. When you write, always check your target journal's requirements and the latest official PRISMA template. Here we stick to the general idea.

It's simple: on the day you run each search, record the hit count per database. On the day you deduplicate, record the count after deduplication. At each screening stage, record how many you excluded.

Just writing down the numbers on the day you do each step turns the flow diagram into a fill-in-the-blanks exercise at write-up. Numbers reconstructed after the fact, by contrast, will always fail to reconcile somewhere.

The most time-consuming piece of the diagram is the breakdown of exclusions at the full-text stage. You need not just the total, but a count for every reason.

The fix is to define your exclusion-reason categories in advance (ineligible population, different intervention, outcome not reported) and pick one from the list each time you exclude a paper. The "on the spot, in words" habit from our screening article feeds directly into this.

PRISMA is more than the flow diagram — it also includes a checklist of reporting items. Skim it once during the design phase of your review so it doesn't ambush you at write-up.

Which items apply, and how strictly, depends on the review type and where you're submitting. Confirm with your supervisor or team.

For tracking counts, spreadsheets or dedicated review tools are the right fit. Paperfy does not auto-generate flow diagrams.

What Paperfy supports is everything upstream. It's where your full-text decisions and their reasons live alongside each paper's PDF and summary. With the source material behind each reason preserved per paper, reconciling the counts stops being guesswork.

Once the diagram is filled in, verify each stage: records remaining + records excluded = records from the stage above.

If even one line doesn't balance, there's a gap in the record somewhere. The moment this check passes is the moment your review's record is complete.