Ed Joseph B Kadane / John Wiley, £65, pp 318 ISBN 0 471 84680 5

When confronted with the ubiquitous P value, the statistical novice usually concludes (wrongly) that it represents the answer to the clinically important question “What is the probability that treatment A is superior to treatment B?” Yet classical (frequentist) statistical methods–the standard used in clinical research–do not address this question; Bayesian methods do. Bayesian researchers can formally quantify prior beliefs about relative efficacies of treatments (from previously published literature and from “informal” clinical experience), and they can then update these “priors” …