The Extended Continuous Evaluation reliability growth model

Abstract

In 2007 the Defense Science Board convened a Task Force to investigate and make recommendations on changes that would increase the reliability of military systems. In 2008 a report was issued by the Task Force which gives the Task Force findings and recommendations. The Task Force found that the “lack of continuous RAM improvement during design, and the resulting low initial MTBF and low Growth Potential are the most significant reasons that systems are failing to meet their operational suitability requirements.” In addition, the Task Force recommended that “RAM, to include a robust reliability growth program, be a mandatory contractual requirement and document progress as part of every major program review.” The Task Force also noted that, “More importantly, an operational perspective earlier in the developmental process has often proven to be a catalyst to early identification and correction of problems.” See Ref. 3. As a result of these finding it is clear that reliability growth tests need to be implemented and conducted closer to operational, real-word conditions in order to evaluate and grow the reliability under conditions close to actual use conditions. This is referred to as “Operational-Like” reliability growth test and represents a new direction within the Department of Defense. A structured Operational-Like reliability growth test would be testing conducted in accordance with the Mission Profile Testing methodology presented in Crow Ref. 2. The author, as a member of this Task Force, concurs with these findings and recommendations. This paper presents a model that is design for continuous reliability growth evaluation over a single or multiple test phases. The model has applications to reliability growth testing in general and is particularly appropriate for Operational-Like testing.