Reliability fix effectiveness factor estimation

A practical, statistically sound methodology is developed for estimating the average fix-effectiveness factor for corrective actions implemented during a reliability growth test phase. A fix-effectiveness factor is defined to be the percent decrease in a problem failure mode due to a corrective action. The approach utilizes the reliability growth projection model developed by L.H. Crow (1974). This model projects the reliability at the beginning of phase II of development testing based on failure data from phase I of development testing and assumes subjective fix-effectiveness factors. The authors reversed this process to estimate an average fix-effectiveness factor using the model and failure data from phase I and phase II. This approach is based on a number of assumptions which are developed and discussed in detail. Examples illustrating the practical application of the procedure are given