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.
Thompson
S G
SG
Medical Statistics Unit, London School of Hygiene and Tropical Medicine, UK.
Pocock
S J
SJ
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