Background Trends in medical education have reflected the patient safety movement's initial focus on systems. While the role of cognitive-based diagnostic errors has been increasingly recognised among safety experts, literature describing strategies to teach about this important problem is scarce.

Methods 48 PGY-2 internal medicine residents participated in a three-part, 1-year curriculum in cognitive bias and diagnostic error. Residents completed a multiple-choice test designed to assess the recognition and knowledge of common heuristics and biases both before and after the curriculum. Results were compared with PGY-3 residents who did not receive the curriculum. An additional assessment in which residents reviewed video vignettes of clinical scenarios with cognitive bias and debiasing techniques was embedded into the curriculum.

Results 38 residents completed all three parts of the curriculum and completed all assessments. Performance on the 13-item multiple-choice knowledge test improved post-curriculum when compared to both pre-curriculum performance (9.26 vs 8.26, p=0.002) and the PGY-3 comparator group (9.26 vs 7.69, p<0.001). All residents correctly identified at least one cognitive bias and proposed at least one debiasing strategy in response to the videos.

Conclusions A longitudinal curriculum in diagnostic error and cognitive bias improved internal medicine residents’ knowledge and recognition of cognitive biases as measured by a novel assessment tool. Further study is needed to refine learner assessment tools and examine optimal strategies to teach clinical reasoning and cognitive bias avoidance strategies.