Diagnostic Reasoning by Expert Clinicians: What Distinguishes Them From Their Peers?

Objectives Expert clinicians (ECs) are defined in large part as a group of physicians recognized by their peers for their diagnostic reasoning abilities. However, their reasoning skills have not been quantitatively compared to other clinicians using a validated instrument. Methods We surveyed Internal Medicine physicians at the University of Iowa to identify ECs. These clinicians were administered the Diagnostic Thinking Inventory, along with an equivalent number of their peers in the general population of internists. Scores were tabulated for structure and thinking, as well as four previously identified elements of diagnostic reasoning (data acquisition, problem representation, hypothesis generation, and illness script search and selection). We compared scores between the two groups using the two-sample t-test. Results Seventeen ECs completed the inventory (100%). Out of 25 randomly-selected non-EC internists (IM), 19 completed the inventory (76%). Mean total scores were 187.2 and 175.8 for the EC and the IM groups respectively. Thinking and structure subscores were 91.5 and 95.71 for ECs, compared to 85.5 and 90.3 for IMs (p-values: 0.0783 and 0.1199, respectively). The mean data acquisition, problem representation, hypothesis generation, and illness script selection subscores for ECs were 4.46, 4.57, 4.71, and 4.46, compared to 4.13, 4.38, 4.45, and 4.13 in the IM group (p-values: 0.2077, 0.4528, 0.095, and 0.029, respectively). Conclusions ECs have greater proficiency in searching for and selecting illness scripts compared to their peers. There were no statistically significant differences between the other scores and subscores. These results will help to inform continuing medical education efforts to improve diagnostic reasoning.