Too frequently in the past, trade studies have been
performed on design alternatives to meet specific performance or reliability
requirements only when a problem was identified, not to review and optimize
all design areas for the purpose of avoiding problems.
The current DoD definition of trade studies is the "evaluation of concepts, policies, techniques, methods, and systems in terms of their costs and effectiveness to determine preferred employments of the several forces and development of projects, postures, and strategies which optimize the attainment of U.S. objectives in potential or actual conflict." In theory this sounds rather all-inclusive. Because a strong emphasis is placed on mission requirements, however, the studies typically do not include total system technical issues in practice. No specific guidelines or checklists are used to ensure completeness of the tradeoffs performed. These studies are initiated by the procuring agency and there is significant concern over their ability to technically analyze and evaluate complex, sophisticated projects effectively. In addition, the studies are performed generally during FSD as a singular event, and in many cases are not available totally to the contractor prior to the start of hardware design. The unfortunate consequence in many instances is that the selected alternative is inadequate for the perceived need, resulting in compromised mission readiness and effectiveness.
Best practice in FSD requires that current definition
be interpreted as a study of design and production alternatives culminating in
a selection that best balances the need against what is achievable
realistically. Considerations to be included are mission effectiveness, cost
comparisons, producibility, advantages/disadvantages, and project risk in
terms of schedule, cost, and technical issues. Further, these FSD studies
should extend and augment the tradeoff studies conducted during the conceptual
phase by the government and concept-phase contractor personnel. Until the
critical design review, the contractor is responsible for continuing tradeoffs
at the detailed design level to assure as "fine-tuned" a design as possible.
These subsequent studies are continual and iterative as the design develops
and matures. All potential program or design selection options thus will have
been exercised throughout the process to assure the timely deployment of a
system that meets the mission requirements.