- BACKGROUND: Cognitive forcing strategies, a form of metacognition, have been advocated as a strategy to prevent diagnostic error. Increasingly, curricula are being implemented in medical training to address this error. Yet there is no experimental evidence that these curricula are effective. DESCRIPTION: This was an exploratory, prospective study using consecutive enrollment of 56 senior medical students during their emergency medicine rotation. Students received interactive, standardized cognitive forcing strategy training. EVALUATION: Using a cross-over design to assess transfer between similar (to instructional cases) and novel diagnostic cases, students were evaluated on 6 test cases. Forty-seven students were immediately tested and 9 were tested 2 weeks later. Data were analyzed using descriptive statistics and a McNemar chi-square test. CONCLUSIONS: This is the first study to explore the impact of cognitive forcing strategy training on diagnostic error. Our preliminary findings suggest that application and retention is poor. Further large studies are required to determine if transfer across diagnostic formats occurs.