Decisions, which are responses to questions such as “What shall we do?” and scientific conclusions, which are responses to questions such as “What are the facts?” are sufficiently different to justify the development of a decision methodolgy different from the classical Scientific Method which guides scientific research. The environment in which health care decisions are embedded, i.e., the life cycle of a health program or project, imposes requirements for a capability to communicate, discuss, review, and track the factors on which decisions are based. The information elements needed for decision making (alternatives, states, outcomes, risk, values), as well as the process needed to generate these decision elements, are described and the additional requirements which they impose on a decision methodology (rationality and the early formulation of an evaluation model) are identified. Decision and utility theory provide a philosophical framework plus two essential ingredients for explicitly implementing the decision process: (1) a rational basis for explicitly measuring preferences (value judgments) on a “utility” scale and (2) a rational rule for making decisions when outcomes are uncertain, i.e., maximize expected utility. A general objective function which combines measures of value (utility) and estimates of risk (probability) into an expression representing the computation of expected utility is presented and discussed. The objective function and the relationships of its elements to the activities of the decision process are illustrated with a relatively simple example. Some implications of simplified special cases of the general objective function are pointed out.