Diagnostic Reasoning

This chapter describes the diagnostic process and provides illustrations from the author’s experience. It notes that the clinical encounter has parallels in hypothetico-deductive reasoning, sharing key elements but not the sequential structure. It refers to the consensus that the thinking of experienced clinicians seldom follows a simple sequence and is driven by intuition, augmented by analytical approaches. Suggested is that success depends on their synergistic function. It argues that the greatest challenge in diagnostic reasoning is the need to integrate imperfect information to synthesize a coherent conclusion. It notes that the cognitive mechanisms are complex, obscure, and prone to error. It describes common biases and argues that both cognitive and affective bias are potent sources of error. The chapter proposes that the model of diagnostic reasoning implicit in traditional medical education should be replaced by a more explicit and complex description incorporating these insights.