Often during a system Product Development program external factors or requirements change, forcing system design change. This uncertainty adversely affects program outcome, adding to development time and cost, production cost, and compromise to system performance. We present a development approach that minimizes the impacts, by considering the possibility of changes in the external factors and the implications of mid-course design changes. The approach considers the set of alternative designs and the burdens of a mid-course change from one design to another in determining the relative value of a specific design. The approach considers and plans parallel development of alternative designs with progressive selection of options, including time-versus-cost tradeoffs and the impact change-costs. The approach includes a framework of the development process that addresses design and integration lead-times, and their relationship to the time-order of design decisions, and the time-dependent burden of design changes
