At NASA we have been developing and applying a risk management framework, "Defect Detection and Prevention" (DDP). It is based on a simple quantitative model of risk and is supported by custom software. We have used it to aid in study and planning for systems that employ advanced technologies. The framework has proven successful at identifying problematic requirements (those which will be the most difficult to attain), at optimizing the allocation of resources so as to maximize requirements attainment, at identifying areas where research investments should be made, and at supporting tradeoff analyses among major alternatives. We describe the DDP model, the information that populates a model, how DDP is used, and its tool support. DDP has been designed to aid decision making early in development. Detailed information is lacking at this early stage. Accordingly, DDP exhibits a number of strategic compromises between fidelity and tractability. The net result is an approach that appears both feasible and useful during early requirements decision making.
['Martin S. Feather', 'Steven L. Cornford']
Quantitative risk-based requirements reasoning