Meta-analysis and its problems

BMJ. 1994 Sep 24;309(6957):789-92. doi: 10.1136/bmj.309.6957.789.


Including all relevant material--good, bad, and indifferent--in meta-analysis admits the subjective judgments that meta-analysis was designed to avoid. Several problems arise in meta-analysis: regressions are often non-linear; effects are often multivariate rather than univariate; coverage can be restricted; bad studies may be included; the data summarised may not be homogeneous; grouping different causal factors may lead to meaningless estimates of effects; and the theory-directed approach may obscure discrepancies. Meta-analysis may not be the one best method for studying the diversity of fields for which it has been used.

Publication types

  • Review

MeSH terms

  • Data Collection
  • Humans
  • Meta-Analysis as Topic*
  • Multivariate Analysis
  • Regression Analysis
  • Selection Bias
  • Sensitivity and Specificity