Current guidance in the Cochrane Handbook Julian Higgins MRC Biostatistics Unit, Cambridge Co-Editor, Cochrane Handbook for Systematic Reviews of Interventions Cochrane Empty Reviews Project Meeting, 16 June 2011

Concluding comments (1/2) Cochrane reviews should be scientific reviews and as such must not draw conclusions based on data that are not part of the review. –Such evidence suffers from all the problems of narrative reviews that we strive so hard to avoid. If no reliable evidence is found, this needs to be reported clearly, and not middied with unreliable evidence If it is realised after the fact that reliable evidence was excluded, the reviewers got their eligibility criteria wrong in the first place. –You can’t fix that by post hoc cherry picking

Concluding comments We do need to think about the relevance of reviews to decision makers, who often want the best available evidence rather than the available good evidence. –Perhaps a paradigm shift is necessary, and many are working on this (e.g. NRSMG). –But to revolve the discussion around “empty reviews” is not helpful.