Using comprehensive feature lists to bias medical diagnosis.

Clinicians routinely report fewer features in a case than they subsequently agree are present. The authors report studies that assess the effect of considering a more comprehensive description than physicians usually offer. These comprehensive descriptions were generated from photographs of dermatology and internal medicine and were complete and accurate. Groups of clinicians of varying expertise were asked to offer a diagnosis based solely on the comprehensive verbal description. This initial exercise decreased the subsequent diagnostic acumen of experienced participants with the photographs relative to a group that initially diagnosed from the photographs. Reasons that the initial consideration of a list of features, all of which are present in the photograph, would decrease diagnostic accuracy are discussed.