Estimating the management strategy for reliability growth planning

Two models that are used in government and industry for constructing a Planned Growth Curve are the Extended Planning model and the PM2 Planning model. Both of these models require various input information regarding the system configuration, effectiveness of correction actions, and the decision process for deciding if a failure mode is corrected or not corrected. The Extended model also requires information on the rate of discovering new problem failure modes. These models require more information regarding the system, corrective action, and management than other models that are used for planning. One important parameter that both models require as input is the Management Strategy parameter. This particular input parameter has a significant influence on the growth potential, the initial reliability on the growth curve, and the overall shape of the planned growth curve. When a new failure mode is discovered in test a management decision is made to either not fix this failure mode with a corrective action (Type A mode) or fix this failure mode with a corrective action (Type B mode). The Management Strategy parameter is the fraction of the initial system failure intensity that is planned to be in the Type B group. The Management Strategy parameter is a measure of how aggressive corrective actions are incorporated into the design. For a system consisting entirely of new, unproven technology, the Management Strategy parameter can be expected to be high, i.e. 0.95. For other systems that use existing technology in the design the opportunity for corrective actions may be less. For these systems the Management Strategy parameter is lower. While a 0.95 value may be desirable and in fact realistic for a development program consisting entirely of new technology and new research and development, it is not realistic for many systems being developed today using existing technology in the design solution. This paper presents a methodology useful for estimating the Management Strategy parameter for systems consisting of new technology, existing technology, or a combination of both.