First Aid for Systematic Reviews

On this page, we provide you with answers to some common questions about Systematic reviews. We describe questions on general characteristics, strengths, and weaknesses of this study design. We hope that more people will perform systematic reviews and that its results are better understood. 

This week    Do I exclude studies that do not report any relevant outcomes from my systematic review?

Studies that report no relevant outcomes should not be excluded from systematic reviews (see also MECIR standard C8). If a study fails to report outcomes, this does not mean that the study did not measure these outcomes. Information on other outcomes may be available from the authors.

This has to do with outcome reporting bias, i.e. bias that arises because statistically significant results are more likely to be reported, whereas this is less likely for statistically non-significant results. Outcome reporting bias is an important threat to the validity of systematic reviews.

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