title: How to read and understand and use systematic reviews and meta-analyses.
abstract: OBJECTIVE
  Systematic reviews and meta-analyses are increasingly frequently used in the evaluation of medical treatments. This review explains the principles of the methodology, significance and limitations of systematic reviews.
  
  
  METHODS
  Short review article.
  
  
  RESULTS
  In contrast to conventional reviews, systematic reviews use a structured approach in retrieving, analyzing and interpreting the evidence. A comprehensive search strategy is applied to identify all relevant trials. Study selection and data extraction is performed independently by at least two reviewers. The data are usually synthesized in a meta-analysis applying statistical methods to examine homogeneity. Funnel plots and other statistical methods are applied to detect publication bias.
  
  
  CONCLUSIONS
  Due to the enormous amount of scientific information published every year, systematic reviews and meta-analyses have become indispensable methods for the evaluation of medical treatments.
authors.affiliation: Klinik and Poliklinik für Psychiatrie and Psychotherapie, Technische Universität München, München, Germany. Stefan.Leucht@lrz.tum.de
authors.forename: S
authors.initials: S
authors.lastname: Leucht
authors.forename: W
authors.initials: W
authors.lastname: Kissling
authors.forename: J M
authors.initials: JM
authors.lastname: Davis
mesh_terms: D015706:Bibliometrics; D005069:Evaluation Studies as Topic; D006801:Humans; D055811:Journal Impact Factor; D015201:Meta-Analysis as Topic; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic; D012196:Review Literature as Topic; D013223:Statistics as Topic; D009626:Terminology as Topic