A clinician’s ability to diagnose accurately is central in assessing prognosis and prescribing effective treatments. However, the strategies clinicians use to arrive at a diagnosis, particularly in primary care, make only a small contribution to current research and the medical curriculum.1 Seminal research in the 1970s showed that the commonly taught sequential approach to history taking and examination, resulting in differential diagnosis and ultimately a final diagnosis, is not what practitioners do in reality.2 3 Researchers observed that diagnostic hypotheses are made early in the consultation and guide subsequent history and examination, in a process of hypothetico-deductive reasoning.2 This work sparked debate about our understanding of the complex strategies used in diagnostic reasoning,4 5 but most work has been done away from the clinical setting.

This series of articles aims to set out the strategies and methods that are used by general practitioners (GPs) in routine clinical consultations. To check that these strategies were actually used in practice, we conducted a pilot of diagnostic consultations from our own practices (box).