A quitting study was excluded from a review: read the reason

Start with the review’s question

Cochrane explains that systematic reviews specify study eligibility criteria based on their question and study types. Read that scope before asking why a particular report is absent. A review of one population or comparison is not obliged to include every paper mentioning vaping.

Write the population, intervention, comparator and design restrictions you find. Do not add an outcome restriction merely because the review discusses that outcome; check its actual criteria. The worksheet identifies scope, not whether the review selected the best possible question.

Cochrane: Cochrane Handbook, Chapter 3: Defining inclusion criteria

Locate the exclusion reason

Check the review’s excluded-study table or supplementary material if available. Match the exact report and identifier, since several papers can come from one project. A paper missing from a brief bibliography has not necessarily been screened and excluded.

In a fictional example, a review limits eligibility to randomized comparisons, while a report describes interviews about access barriers. Exclusion under that design criterion does not prove that the interviews are worthless. They answer another question. The example makes no claim about an actual review’s decisions.

Separate scope from appraisal

An exclusion can concern an ineligible population, a different comparison or material that does not meet another stated condition. A quality assessment, where performed, asks a different question about how evidence was produced. Read the recorded reason rather than substituting your preferred explanation.

Do not announce that excluded evidence disproves the review or that included studies are all definitive. If a reason is unclear or seems inconsistent with the stated criteria, prepare a specific question about that report. A general accusation does not fill the missing information.

Consider what the report can still contribute

A report outside one review may offer context or belong in a different evidence question. Identify that limited contribution without inserting its result into a pooled estimate yourself. You also need to distinguish a completed report from a protocol or a different publication from the same project.

Finish with the review criterion, the documented reason and any unanswered question. This reading guide cannot reselect studies, repair a synthesis or recommend personal treatment. It helps prevent “excluded” from becoming a blanket scientific verdict when the actual issue is the review’s defined scope.