The retracted study should be listed in the “excluded articles” studies” section, with the reason noted, and including a citation to the published retraction notice. This reason must be noted using neutral language and should not accuse authors of scientific misconduct. If there is any doubt about the phrasing of such a note, the CRG must contact the Associate Editor and Senior Editor for the CRG Network (who will refer on to the Deputy Editor in Chief) before publication of the Review.
- Consider assessing the study against an (unvalidated) checklist such as the REAPPRAISED checklist for evaluation of publication integrity.
- If the article reports a clinical trial, check the article for a trial registration number and search the relevant trial registry to determine whether the study was registered prospectively. The WHO expects that all clinical trials are prospectively registered in a WHO Registry Network approved registry. One of the minimum standards set out for trial registries in the International Standards for Clinical Trial Registries Trial is that registries must obtain written third-party confirmation of a trial’s existence as part of the registration process. Lack of prospective registration can be one sign of a problematic study, however it should be noted that lack of evidence of prospective trial registration alone is not considered sufficient to exclude a study from a review, and there is no empirical evidence that inclusion of only prospectively registered studies in a review guarantees the inclusion of only trustworthy studies. For some types of study designs, such as qualitative research, prospective registration will not be possible.
- If the article reports a clinical trial that was prospectively registered, check the list of outcomes in the trial registry entry against the outcomes that were reported in the study.
- Check the article for a statement of whether approval from an ethics committee was granted for the study and whether this statement includes the name of the ethics committee granting the approval, and an approval reference number. Please note that lack of a statement regarding ethics approval does not mean that a study did not have ethics approval or that the study is untrustworthy and should not be included in a Cochrane Review.
- Look for potential ‘red flags’ in the article, for example:
- Is the number of patients recruited within the timeframe with the condition plausible?
- Do the numbers of participants add up?
- Are there obvious inconsistencies in the article e.g. different country specified in different parts of the article?
- Are the authors affiliations all from a different country than the country the study is reported to have taken place in?
- Is there a realistic response rate or number of participants lost to follow up?
- Is the number of authors plausible for the study design? (e.g. is it a single author article reporting a randomised control trial)
- Is there significant overlap in text/data with another published articles by the same or different authors without explanation?
- Check to see if the study has been included or excluded from any other Cochrane Reviews and, if so, if any additional information is available. Consult with an information specialist for help with this.
- Consider further statistical assessment of the study data:
- An analysis of baseline data (e.g. age) can be used to identify unlikely baseline data, which may be the result of honest error, poor methodology or misconduct. For further information, see for example Carlisle 2015. Consult with a statistical editor for advice for advice about this.
- Sensitivity analyses can be used to prove that the findings from a systematic review are not dependent on arbitrary or unclear decisions and are therefore useful when considering whether one or more studies should be included in a meta-analysis. For further information, see the Cochrane Handbook, chapter 9.7 Sensitivity analyses.
- Consider searching for studies authored by one or more authors of the study about which there are concerns, even if the studies were ineligible for inclusion in the current Cochrane Review, to look for retractions, Expressions of Concern and editorial comments. It is important to note that a retraction of another article by an author does not necessarily indicate that there is a problem with other studies on which they are an author.