PRISMA 2020: records, reports and studies explained
The three terms, as defined by PRISMA 2020
- Record
- The title or abstract (or both) of a report indexed in a database or website. A search returns records.
- Report
- A document supplying information about a study: a journal article, preprint, conference abstract, study register entry, clinical study report, dissertation or similar.
- Study
- An investigation, such as a clinical trial, with a defined group of participants and one or more interventions and outcomes. A study can have several reports.
How the numbers flow, with a worked example
These are the example numbers in the free PRISMA 2020 flow diagram generator, which calculates every total for you.
| Stage | Unit | Example | How it is calculated |
|---|---|---|---|
| Identified | Records | 5,508 | 5 databases (5,422) + registers (86) |
| Removed before screening | Records | 2,176 | Duplicates 2,164 + other reasons 12 |
| Screened | Records | 3,332 | 5,508 − 2,176 |
| Excluded at title and abstract | Records | 3,214 | Reported as a total |
| Sought for retrieval | Reports | 118 | 3,332 − 3,214 |
| Not retrieved | Reports | 6 | Full text unavailable |
| Assessed for eligibility | Reports | 112 | 118 − 6 |
| Excluded at full text | Reports | 94 | With reasons: design 51, population 18, comparator 12, outcome 9, same cohort 4 |
| Included | Reports and studies | 24 reports of 18 studies | 18 reports from databases + 6 from citation searching; some studies have more than one report |
Mistakes reviewers spot most often
- Counting reports as studies. If a trial has a main paper and a follow-up, that is two reports but one study.
- Arithmetic that does not add up. Each box should follow from the boxes above it.
- Duplicates listed as exclusions. They belong in "records removed before screening".
- Full-text exclusions without reasons. Every report excluded at full text needs a reason and a count.
- Other search methods mixed into the database column. Websites, organisations and citation searching have their own column.
- Using the new-review template for an update. Updated reviews have separate PRISMA 2020 templates.
Sources
Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. Official PRISMA 2020 flow diagram templates.
Frequently asked questions
What is the difference between a record and a report in PRISMA 2020?
A record is the title and/or abstract of a report as it appears in a database or website. A report is the document itself, such as a journal article, preprint, conference abstract or trial register entry. You screen records, then retrieve and assess reports.
Why does the PRISMA 2020 diagram count studies and reports separately?
One study can be described in several reports, such as a main paper, a follow-up and a conference abstract. Counting both shows readers how many independent studies the review includes and how many documents describe them.
Should duplicates be counted as excluded records?
No. Duplicates are removed before screening and reported in their own box. Records excluded at title and abstract screening are a separate number.
Do I need reasons for every excluded record?
No. PRISMA 2020 asks for reasons for reports excluded at full-text assessment. Records excluded at title and abstract screening are reported as a total.