5 Diagnostic Decision Support Systems

Since primeval times, mankind has attempted to explain natural phenomena using models. For the past four decades, a new kind of modeler, the healthcare informatician, has developed and proliferated a new kind of model, the Clinical Diagnostic Decision Support System (DDSS). Modeling historically was, and still remains, an inexact science. Ptolemy, in the “Almagest,” placed the earth at the center of the universe and could still explain why the sun would rise in the east each morning. Newton’s nonrelativistic formulation of the laws of mechanics works well for earth-bound engineering applications. Past and present DDSS incorporate inexact models of the incompletely understood and exceptionally complex process of clinical diagnosis. Yet mankind, using imperfect models, has built machines that fly, and has cured many diseases. Because DDSS augment the natural capabilities of human diagnosticians, they have the potential to be employed productively. This chapter presents a definition of clinical diagnosis and of DDSS; a discussion of how humans accomplish diagnosis; a survey of previous attempts to develop computer-based clinical diagnostic tools; a discussion of the problems encountered in developing, implementing, evaluating, and maintaining clinical diagnostic decision support systems; and a brief discussion of the future of such systems.