Effects of case revisitation during deliberate reflection on medical students' diagnostic accuracy: a randomized experiment.

OBJECTIVES: Deliberate reflection (DR) is an instructional strategy that enhances clinical reasoning by prompting learners to systematically compare diagnostic hypotheses with case findings. DR protocols often allow learners to revisit the written case during reflection, which may reduce cognitive effort but limit the benefits of effortful retrieval for long-term retention. This study examined whether allowing or restricting case revisitation during DR affects medical students' diagnostic performance. METHODS: We conducted a randomized, two-arm experimental study with 67 third- and fourth-year medical students enrolled in a six-year undergraduate medical program in Brazil. During the intervention phase, after providing an initial diagnosis, students engaged in DR either with or without access to the case description. After a 15-day interval, participants diagnosed four cases of previously studied diseases and four cases of adjacent diseases. Outcomes included diagnostic accuracy, confidence, and recall of correct propositions, analyzed using a generalized linear mixed model. RESULTS: No overall group differences were found in diagnostic accuracy. However, a significant interaction emerged between group and disease type (χ2 (1)=7.68, p=0.006). For previously studied diseases, students in the without-access-DR group performed better (OR=1.77, 95 % CI [0.76, 2.78], p=0.050), whereas for adjacent diseases, those in the with-access-DR group performed better (OR=0.56, 95 % CI [0.24, 0.89], p=0.050). Diagnostic accuracy was positively associated with confidence (OR=1.12, 95 % CI [1.01, 1.24], p=0.028) and recall (OR=1.06, 95 % CI [1.01, 1.12], p=0.027). CONCLUSIONS: Restricting case revisitation enhanced accuracy for previously studied diseases, consistent with retrieval effort theory, whereas allowing revisitation supported transfer to adjacent diseases.