Reliabilitv Growth During a Development Testing Progiam

The problem of estimating reliability of a system undergoing development testing is examined. It is assumed that the test program is conducted in K stages and that similar items are tested within each stage. In addition, it is assumed that the probability of an inherent failure, q 0, remains constant throughout the test program while the probability of an assignable cause failure in the i-th stage, qi , does not increase with i. The number of inherent failures, of assignable cause failures, and of successes is recorded in each stage. Maximum likelihood estimates of q 0, q i (i = 1, 2, …,K) and a conservative confidence bound for the reliability in the K-th stage are obtained. Numerical examples to illustrate the methods are given.