[Medical decision making: its history and technical terms].

Medical decision making, an application of decision sciences to medicine, has been increasingly recognized as an important clinical armamentarium in the past several decades. Clinical medicine abounds in uncertainties arising from the very nature of clinical data and physicians' judgments. These uncertainties provide room for decision sciences to be widely used in clinical medicine. There are two major research areas in medical decision making, i.e., prescriptive and descriptive approaches. The prescriptive approach, an endeavor to explore how decisions should be made, is quantitative and probabilistic, and employs decision analytical procedures which are designed to maximize expected value or utility. An example of a decision tree is shown as well as such essential technical terms as decision node, chance node, averaging out, folding back, sensitivity, specificity, predictive values, Bayes' theorem, and expected value of clinical information. The descriptive approach, on the other hand, is related to how people behave. In this context, strict meaning of judgment and decision making, some heuristics and psychological pitfalls, and the necessity of elucidating patients' preferences, though difficult, are recapitulated.