A Fully Bayesian Criterion for Sample Size Determination in Clinical Trials

In this paper we discuss a Behavioural Bayes approach to the sample size question in clinical trials in which the data are assumed to come from a normal distribution for which the mean and variance are both unknown. A fully Bayesian framework is considered. The optimal sample size is obtained by maximizing the expected net benefit which is the benefit from subsequent use of the new treatment under consideration minus the cost of the trial