Heuristics, normative models, and the value of serial test patterns

This paper deals with living systems at the level of the human organism, including all subsystems. It argues that, in medicine, conclusions about the adequacy of clinical heuristics, vis-à-vis normative models, may be suspect until the models are more adequately designed and the heuristics better defined. Through a theoretical analysis, it shows that dynamic information, ordinarily ignored in normative models yet often present in biological systems, can have a profound impact on the cost-effectiveness of test use. Empirically, it also shows that explicit clinical policies ignoring dynamic test patterns can lead to substantial loss in diagnostic information. These results motivate research on clinical strategies for using dynamic information. They also suggest unmet needs in evaluating tests, providing decision support, and educating physicians in cost-effective test use.