title: Commentary. Oligognostic mega-analysis. Is Archie turning in his grave?
abstract: The Cochrane Collaboration has developed guidelines for the conduct of meta-analyses and systematic reviews. When applied to well-conducted short-duration randomized controlled trials, meta-analysis can be informative, but seldom in prolonged trials, because of "unblinding", non-adherence, losses to follow-up, and "crossovers". The meta-analysis of observational studies is beset by problems of bias, confounding, variable methodology, and lack of transparency, and is seldom valid. For the evaluation of partly quantitative or non-quantitative studies, systematic reviews using standardized methods have been developed. However, such reviews are inferior to well-conducted qualitative reviews tailored to the specific topics at issue.
authors.affiliation: Department of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town Medical School, Cape Town, South Africa. Electronic address: sydzeev@gmail.com.
authors.forename: Samuel
authors.initials: S
authors.lastname: Shapiro
mesh_terms: D015982:Bias; D006801:Humans; D015201:Meta-Analysis as Topic; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic