Purpose: Although decades of research have yielded considerable insight into physicians' clinical reasoning processes, assessing these processes remains challenging; thus, the authors sought to compare diagnostic performance and the utility of clinical vignette-based assessment under testing conditions designed to encourage either automatic or analytic thought.
Method: This 2011-2012 multicenter randomized study of 393 clinicians (medical students, postgraduate trainees, and faculty) measured diagnostic accuracy on clinical vignettes under two conditions: one encouraged participants to give their first impression (FI), and the other led participants through a directed search (DS) for the correct diagnosis. The authors compared accuracy, feasibility, reliability, and relation to United States Medical Licensing Exam (USMLE) scores under each condition.
Results: A 2 (instructional condition) × 2 (vignette complexity) × 3 (experience level) analysis of variance revealed no difference in accuracy as a function of instructional condition (F[1,379] = 2.44, P = .12), but demonstrated the expected main effects of vignette complexity (F[1,379] = 965.2, P < .001) and experience (F[2,379] = 39.6, P < .001). Pearson correlations revealed greater associations between assessment scores and USMLE performance in the FI condition than in the DS condition (P < .001). Spearman-Brown calculations consistently indicated that alpha ≥ 0.75 could be achieved more efficiently under the FI condition relative to the DS condition.
Conclusions: Instructions to trust one's first impres-sions result in similar performance when compared with instructions to consider clinical information in a systematic fashion, but have greater utility when used for the purposes of assessment.