Investigating the Influence of Training Difficulty on the Learning Outcomes of Medical Students

ABSTRACT Background Determining an optimal training difficulty level for the best learning outcome is a crucial goal for adaptive educational systems. The literature supports the Inverted U ‐shape Hypothesis, suggesting that the ideal challenge level for learning is neither too easy nor too difficult. However, this optimal point depends on the type of training and response modality and may vary across domains, necessitating thorough examination before implementing adaptive learning procedures. Objectives This study aimed to investigate the influence of training difficulty on the learning outcomes of French medical students. Methods Using data from a national educational platform, we explored the influence of the mean question difficulty encountered during training, relative to individual student ability, on the learning outcomes of medical students across diverse medical specialties. Importantly, the mean difficulty level varied randomly between students on this platform, mirroring a quasi‐experimental design and enabling a thorough exploration of these effects. We first employed the Elo rating system to estimate the difficulty of platform questions and the evolution of students' abilities. A linear mixed‐effects model was then used, with final exam performance as the main outcome and mean relative question difficulty during training (linear and quadratic terms) as the main predictor. Results and Conclusions Results showed a significant negative quadratic effect of mean relative difficulty on the final exam performance, revealing optimal difficulty levels for each medical specialty. Additionally, the analysis demonstrated that students with high abilities displayed a more pronounced inverted U ‐shaped relationship between training difficulty and final exam scores. This study advances our understanding of optimal training difficulty in the complex realm of medical education, by emphasising the need to acknowledge variability across medical specialties and student abilities.