Assessing the validity of one-part software reliability models using likelihood ratio and early detection tests

To achieve higher accuracy in software failure rate estimates in a field environment, software reliability models that were fit from failure data collected during the test interval are often refit using the combined test interval and field interval data. The validity of this analysis depends on the test and field environments being compatible with respect to the manner in which the software is used. In this paper, we formulate the hypothesis of compatible test and field environments in terms of a statistical hypothesis and develop an appropriate test procedure. The test procedure is illustrated by applying it to a real-life software project.