Group Reliability Predictions

On the basis of an assumed Bayesian model and a set of criteria for judging reliability predictions, it is shown that: 1. Group predictions outperform individual predictions. 2. A weighted average is a satisfactory and perhaps the only satisfactory method of arriving at group predictions. 3. For a series system, group predictions of component reliabilities combined to form a prediction of system reliability are preferred to a group prediction of system reliability. 4. Prior averaging and updating via Bayes´ rule is s-consistent and seems preferable to averaging posterior individual predictions. The intent of this paper is to provide theoretical guidance to the practical problem of group reliability prediction.