This paper outlines the approaches of two apparently competing schools of statistics. The criticisms made by supporters of Bayesian statistics about conventional Frequentist statistics are explained, and the Bayesian claim that their method enables research into new treatments without the need for clinical trials is examined in detail. Several further important issues are considered, including: the use of historical controls and data routinely collected on patients; balance in randomised trials; the possibility of giving information to patients; patient choice and patient (...) autonomy; and how widely the results of clinical trials can be used. It is concluded that good statistical techniques in the design and analysis of medical studies are essential, but the statistical school used in developing such techniques is relatively unimportant. (shrink)