A critical look at some point-process models for repairable systems

The use of a model-driven approach to the analysis of repairable systems is considered and shown to be useful as a way of understanding the characteristics of such a system. However, considerable statistical problems arise from the use of a set of standard model-building elements. In particular, identification problems arise in many of the models. The argument is illustrated by examples from software reliability and mechanical reliability. The conclusion is that, in many cases, the exploratory data-analysis approach is as effective as the use of more sophisticated models.