Defining Differential Diagnosis Skill Progression in Physician Assistant/Associate Students, A Cross-Sectional...

The purpose of this study was to measure benchmarks for the competency "generating a prioritized differential diagnosis" in physician assistant/associate (PA) students as they progress through training and compare these benchmarks to experienced clinicians.

This cross-sectional study used a survey with 3 clinical vignettes of 50 words or less. Each participant was instructed to provide a prioritized list of up to 10 diagnoses for each vignette. The study group included 3 cohorts of PA students-first-year (PAS-1), second-year (PAS-2), and third-year (PAS-3)-and a reference group of experienced clinicians. Outcomes included top slot diagnosis, differential concordance index, emergent diagnoses, organ systems, list length, and time to completion.

Fifty-five students and 9 clinicians participated. PAS-2 and PAS-3 had a greater number of concordant responses and higher accuracy in top slot diagnosis based on agreement with the reference group. With experience, student lists included more emergent diagnoses and more organ system considerations. Clinicians and PAS-1 took significantly less time (340 seconds [SD 141.5, interquartile range (IQR) 226.7-445.8]) to complete all vignettes compared with PAS-2 and PAS-3 (663 seconds [402.5, 310.6-850.1]). Mean list length was progressively greater from PAS-1 (2.9 [1.8, 2-4]) to PAS-3 (6.4 [2.6, 4-8]) with clinicians having the greatest mean list length (6.8 [2.7, 5-9.5]).

Differential diagnosis ability among PA students appears to develop in both breadth and concordance with experienced clinicians. Targeted feedback to students might include increasing list length and considering more organ systems and emergent though less prevalent diagnoses.