Can meta-analyses be trusted?
The enthusiasm for meta-analyses (or overviews) expressed by their proponents is not always shared by the broader medical community. To encourage constructive debate, we adopt a critical perspective on the conduct and interpretation of meta-analysis. We focus particularly on some of the statistical issues, especially heterogeneity between studies, and also on the extrapolation of meta-analysis findings to clinical practice. We conclude that meta-analysis is not an exact statistical science that provides definitive simple answers to complex clinical problems. It is more appropriately viewed as a valuable objective descriptive technique, which often furnishes clear qualitative conclusions about broad treatment policies, but whose quantitative results have to be interpreted cautiously.
Medical Statistics Unit, London School of Hygiene and Tropical Medicine, UK.
S G
SG
Thompson
S J
SJ
Pocock
D015982:Bias; D003627:Data Interpretation, Statistical; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D011225:Pre-Eclampsia / Q000517:prevention & control; D011247:Pregnancy; D012107:Research Design; D013223:Statistics as Topic