An illness script approach in clinical reasoning education: self-reported diagnostic thinking among medical students

Clinical reasoning is a core competency in medical practice and is essential for safe clinical decision-making. Illness script theory provides a cognitive framework for organizing clinical knowledge and supporting diagnostic reasoning. However, evidence on structured illness script–based education among medical clerks and interns remains limited. This study evaluated whether participation in a structured illness script–based clinical reasoning program was associated with differences in self-reported diagnostic thinking among medical clerkship and internship students. This cluster-randomized study was conducted in 2025 at two teaching hospitals affiliated with Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Before participant recruitment, the two hospitals were randomly allocated to the intervention or control condition using a pre-specified coin-toss procedure. A total of 128 medical students participated, including 65 in the intervention group and 63 in the control group. The intervention group received a 12-week structured illness script–based clinical reasoning program in addition to routine clinical education, whereas the control group received routine clinical education and regular lecture-based teaching. Learner satisfaction was also assessed using an eight-item questionnaire. Diagnostic thinking was assessed before and after the intervention using the 41-item Diagnostic Thinking Inventory (DTI), comprising the structure of memory and flexibility in thinking domains. Post-intervention DTI scores were analyzed using analysis of covariance, adjusting for baseline DTI score, age, sex, and educational level. Learner satisfaction was higher in the intervention group than in the control group (35.23 ± 2.25 vs. 32.00 ± 2.70; p < .001). The adjusted post-intervention DTI total score was significantly higher in the intervention group than in the control group (estimated marginal mean, 151.05 vs. 136.41; adjusted mean difference, 14.64 points, 95% CI 9.46–19.81; p < .001). The overall adjusted model was statistically significant ( F (5,122) = 7.92, p < .001, R ² = 0.245, adjusted R ² = 0.214). The adjusted effect of study group was statistically significant ( F (1,122) = 29.39, p < .001, partial η² = 0.194, 95% CI 0.082–0.312). A sensitivity analysis using a generalized linear model with robust covariance estimates yielded a consistent group effect (B = − 14.64, 95% Wald CI − 19.76 to − 9.51; Wald χ²(1) = 31.30, p < .001), supporting the robustness of the primary finding to heterogeneity of error variances. Participation in a structured 12-week illness script–based clinical reasoning program was associated with higher self-reported diagnostic thinking scores and greater learner satisfaction among medical clerks and interns. These findings provide preliminary evidence supporting the potential value of structured illness script–based activities in clinical reasoning education. However, the findings should be interpreted cautiously because the study included only two hospital clusters and the primary analysis was conducted at the individual level, limiting the ability to separate intervention effects from potential hospital-level differences. Multicenter studies with a larger number of clusters, cluster-appropriate analytical methods, and objective performance-based outcomes are needed to determine whether illness script–based education translates into improvements in clinical reasoning performance.