We sought to determine the impact of medical students’ prior experience of assessing peers in the objective structured clinical examination (OSCE) on their clinical performance.
Forty-two year 4 medical students participated in an OSCE comprised of three 10-minute stations (syncope, hemoptysis, and back pain). Each student took part in two iterations of the three-station OSCE as either the examiner or examinee, and student performance was assessed using a checklist by a medical faculty member and a student simultaneously. Students were randomly assigned to two groups and their OSCE scores were compared. Students in the control group were tested at a station first and then participated at the same station as a peer examiner, and those in the intervention group participated as a peer examiner first and then as an examinee. Moreover, student OSCE scores rated by peer examiners were compared with those awarded by faculty to evaluate the accuracy of peer assessment. Following the test, students completed surveys on their perceptions of the usefulness of this formative OSCE.
Student overall OSCE scores did not differ between groups. Students in the study group performed better at the hemoptysis station (p<0.001), but poorer at the syncope station (p<0.01). Student performances at the back-pain station were similar in these two groups (p=0.48). OSCE scores rated by faculty and peer examiners were moderately negatively associated at the hemoptysis station (p<0.05), but no such association was observed at the other two stations. This trend was similar in peer examiners who were high-achievers and low-achievers in OSCEs. Students showed positive perceptions of their experience with this OSCE.
Student experience as peer assessor offers a feasible means of providing them greater access to OSCEs without consuming more resources, although its impact on enhancing performance in the OSCE is likely to differ across stations.

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