Assessing reliability using developmental and operational test data

This paper presents a new reliability assessment model that allows for the combination of developmental and operational data from different test events for continuously operating systems. The model offers an alternative to traditional reliability assessment using a single operational test only. Reliability degradation between developmental and operational testing is explicitly modeled through the use of a nuisance scale parameter, and a complete inference framework is provided via the posterior distribution. The approach serves as a natural extension of the current approach to reliability growth and demonstration used in the Defense industry while explicitly modeling the additional uncertainty that exists in the problem. Analogous Operating Characteristic (OC) curve quantities are developed from the posterior distribution. Use of these results will generally lead to tighter uncertainty intervals and result in lower reliability design goals. This approach can help to directly reduce the programmatic risks that may exist due to reliability demonstration in a constrained environment with operational test data alone.