A process of selecting from among several alternatives, which may be either quantitative or qualitative, the best alternative in order to solve a problem or resolve a conflict. The elements of the process are: derivation of a model which describes the problem, selection of criteria to serve as standards, determination of constraints that act as limitations to various alternatives, and an optimization which results in the best solution consistent with the objectives of the decision maker. The analysis of complex situations with many alternatives and many possible consequences is facilitated by the mathematics of decision theory.