PRISMA flow diagram example
Updated 2026-09-24
The easiest way to understand a PRISMA flow diagram is to follow the numbers through one. This example uses a review that searched three databases and also used other methods.
Example 1: databases only
A review searched three databases:
| Stage | Number | Check |
|---|---|---|
| PubMed | 412 | |
| Embase | 520 | |
| CENTRAL | 168 | 412 + 520 + 168 = 1,100 records identified |
| Duplicates removed | 260 | 1,100 − 260 = 840 screened |
| Records excluded at title and abstract | 700 | 840 − 700 = 140 reports sought |
| Reports not retrieved | 10 | 140 − 10 = 130 assessed |
| Reports excluded with reasons | 90 | 130 − 90 = 40 studies included |
Exclusion reasons should add to 90, for example wrong population (35), wrong outcome (30), wrong study design (25).
Example 2: adding other methods
Suppose the same review also searched websites (22), organisations (8) and citation searching (30), giving 60 records from other methods. Of these, 48 reports were sought, 6 could not be retrieved, and 42 were assessed. Thirty were excluded with reasons and 12 were included. The two streams then merge, so the review reports 40 + 12 = 52 studies included.
What to notice
- Each box is the previous box minus what was removed.
- Exclusion reasons add up exactly to the excluded total.
- Records (search results) and reports (documents you tried to read in full) are counted separately.
Try it with your own numbers
Type these numbers into the free PRISMA flow diagram generator to see this example drawn instantly, then replace them with your own. New to the layout? Read what a PRISMA flow diagram is or how to make one.
Quick answers
Do the numbers in the example matter?
No. They are illustrative. What matters is that your own boxes add up and that every exclusion has a reason.
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.