An updated review has a history. A diagram that shows only a new search can leave a reader unable to see how earlier evidence relates to the current review. Before drawing a selection flow, identify what the review is updating and which discovery routes were used.
The official PRISMA flow-diagram page provides distinct templates for new and updated reviews, with variants for database/register searches alone or with other sources. It describes the diagrams as showing identification, inclusion, exclusion and exclusion reasons. Template selection should reflect the work actually performed.
Ask two questions before choosing a file
- Is this a new review or an update of an identifiable earlier review?
- Were records located only through databases and registers, or through additional routes as well?
Keep the answers in the review’s methods notes. They should arise from the documented process, not from whichever diagram looks simplest to fill.
Preserve the earlier-review link
For an update, retain the prior review’s citation and the relationship between its included material and the new review. Record any re-evaluation of earlier eligibility separately from newly identified material. Do not assume that every earlier inclusion remains eligible if the review’s question or criteria changed.
A practical reconciliation sheet can link the previous evidence list, the newly located reports and the current inclusion decisions. This helps explain the final diagram without inventing a missing search stage or silently dropping earlier work.
Keep discovery routes distinguishable
If material came from reference checking or another documented route, preserve that provenance. It may overlap with database results, so record the matching decision rather than adding every route’s total as though each item were unique.
The flow diagram communicates selection history. It does not establish that the search was comprehensive or the evidence clinically reliable. A neat diagram cannot repair an undocumented review process.
No review counts or diagram were produced here. This guide helps a reader choose the appropriate template family and identify the records needed to populate it honestly.
Primary reporting guidance read 21 October 2026. Suggested note structures and explicitly fictional examples are editorial. No clinical result is evaluated.
Source: PRISMA2020 new and updated review flow templates. Related discussion: health information source quality.
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