Making robust assessments of specialist trainees' workplace performance

Background. Workplace-based assessments should provide a reliable measure of trainee performance, but have met with mixed success. We proposed that using an entrustability scale, where supervisors scored trainees on the level of supervision required for the case would improve the utility of compulsory mini-clinical evaluation exercise (CEX) assessments in a large anaesthesia training program. Methods. We analysed mini-CEX scores from all Australian and New Zealand College of Anaesthetists trainees submitted to an online database over a 12-month period. Supervisors' scores were adjusted for the expected supervision requirement for the case for trainees at different stages of training. We used generalisability theory to determine score reliability. Results. 7808 assessments were available for analysis. Supervision requirements decreased significantly (P < 0.05) with increased duration and level of training, supporting validity. We found moderate reliability (G > 0.7) with a feasible number of assessments. Adjusting scores against the expected supervision requirement considerably improved reliability, with G > 0.8 achieved with only nine assessments. Three per cent of trainees generated averagemini-CEX scores below the expected standard. Conclusions. Using an entrustment scoring system, where supervisors score trainees on the level of supervision required, mini-CEX scores demonstrated moderate reliability within a feasible number of assessments, and evidence of validity. When scores were adjusted against an expected standard, underperforming trainees could be identified, and reliability much improved. Taken together with other evidence on trainee ability, the mini-CEX is of sufficient reliability for inclusion in high stakes decisions on trainee progression towards independent specialist practice.