On analysing warranty data from repairable items

Fitting models to failure data is an important topic in reliability. The resulting models can be useful both for manufacturers as well as for end-users. In this paper we provide details of some methods from the literature which can be used as a starting point when analysing and fitting models to failure data from repairable items. In particular we focus on obtaining analytical estimates of the intensity of a non-homogeneous Poisson process. We illustrate some of these methods on failure data from the warranty database of a major car manufacturer