Characterizing reliability in a product/process design-assurance program

Just as estimates of cost and program timing are critical factors to be known and monitored during a new product development program, so too is the reliability perspective. This paper describes an approach to reliability modeling that encompasses the impact of both product and manufacturing process design on the distribution (characterizing the uncertainty) of reliability over time. It further describes the elicitation of expert judgment which is used to quantify the initial reliability estimate, including uncertainty. Finally, it describes a Bayesian updating approach which is applicable throughout the development program, and which accommodates a wide variety of possible new information. Although the model is rigorous in its execution; a user-friendly approximation is also described which may be useful to the product development team for purposes of test and validation planning.