In the era of systematic reviews, does the size of an individual trial still matter?

Abstract

Background to the debate: Systematic reviews that combine high-quality evidence from several trials are now widely considered to be at the top of the hierarchy of clinical evidence. Given the primacy of systematic reviews - and the fact that individual clinical trials rarely provide definitive answers to a clinical research question - some commentators question whether the sample size calculation for an individual trial still matters. Others point out that small trials can still be potentially misleading. © 2008 Guyatt et al.