Systems engineering and program management (SE/PM) constitute a large portion of the acquisition cost of military aircraft and guided weapons systems. The goal of this study was the development of a set of cost-estimating relationships that can be used to estimate the SE/PM cost element for development and production of aircraft and weapons programs. The authors canvassed government and industry personnel to learn about current techniques for estimating SE/PM costs, and they collected historical data from several aircraft and weapons programs to investigate trends in SE/PM costs over time and to generate methods that cost analysts can use early in the life cycle of a program when little cost information is available. The authors also investigated the effects on SE/PM costs from acquisition reform, including the reduction in the number of military specifications and standards, the use of integrated product and process teams, and the trend toward evolutionary acquisition."