The CHART trials: Bayesian design and monitoring in practice. CHART Steering Committee.

In this paper we describe the design and monitoring of two large randomized trials being conducted through the British Medical Research Council (MRC) Cancer Trials Office. In particular we discuss the issues involved in the design of the trials, specifying the null and alternative hypotheses and how the design has influenced the monitoring procedure used. From these two examples, and some other MRC experiences, we suggest some basic considerations which could be applied to many MRC and other trials.