Using spaced repetition to teach histopathology significantly improves diagnostic skills: A randomized within-participant evaluation.

The vast and rapidly evolving knowledge base in histopathology poses a significant challenge to long-term retention. We report here, in a randomized within-participant exposure-controlled evaluation, the efficacy of spaced repetition (SR), a technique for efficient memorization using repeated review of content according to a schedule determined by an algorithm to improve long-term retention. The study recruited trainees and certified pathologists. Participants were given access to an online e-learning module, consisting of a series of short videos, and were randomly assigned to one of two different sets of spaced repetition material. Three months after inclusion, their diagnostic performance was evaluated online using 20 previously unseen cases. The study included 337 participants in 2023. The evaluation and the feedback questionnaire were completed by 23% (79/337), with 58% (46/79) using the SR material. Learning via SR improved diagnostic performance both in accuracy and speed within participants: each participant scored significantly higher on diagnoses they had reviewed using SR compared to those they had not (mean score: 7.3/10 vs. 5.4/10; paired mean difference +1.9 points, p < 0.001, n = 42), and completed these same cases in significantly less time (paired median difference -1.4 min, p = 0.018). Participants were highly satisfied with this learning technique, with 90% expressing intent to reuse it. The findings suggest that SR can be used to improve diagnostic accuracy and speed of pathologists. SR has a strong effect on acquisition of diagnostic skills in histopathology and its use should be promoted in initial training and continuing medical education.