Administration of a Parallel, Simultaneous Objective Structured Clinical Examination to Accommodate a Large Class of Students

The use of an objective structured clinical examination (OSCE) to evaluate the clinical abilities of second-year medical students at the end of an introduction to clinical medicine course in 2 successive years is reported. Due to the large number of students in our classes, two identical, simultaneous, parallel OSCEs were administered each year. Skills to be evaluated and cases used to measure these skills were determined by a modification of existing methods. The logistic feasibility of administering a large OSCE in this manner was confirmed. A thorough psychometric evaluation of the OSCE was performed, and findings were evaluated. When used in a pass-fail context and calculated as a dependability index with cutoffs, the generalizability of the total OSCE and most individual skills measured was greater than. 8 when the cutoff was 2 SD below the mean score. The number of cases required to achieve a generalizability of. 8 for the total OSCE and each individual skill was fewer than 11. The potential for use of the OSCE in making pass-fail decisions in medical school classes and proposals for modification of the mechanisms of administration and scoring of the OSCE are discussed.