Is test security a concern when OSCE stations are repeated across clerkship rotations?

To examine the issue of test security when the same stations on an objective structured clinical examination (OSCE) are repeated across clerkship rotations. Specifically, is there a significant difference in students' scores on stations repeated in three or four rotations within a single academic year?

The sample consisted of 15 stations in the OSCE given at the end of the third-year surgery clerkship at the Southern Illinois University School of Medicine from 1989-90 through 1993-94. Each station was administered three or four times a year. One-way analyses of variance with contrast coding to test for linear trends were used. Results were considered significant at or below the .05 level.

Only three of the 15 stations showed significant linear trends. A two-part couplet orthopedic station showed a significant decreasing linear trend (p=.0001). Two stations showed significant increasing linear trends: a general surgery couplet station (p=.0004) and a plastic surgery station with an essay question (p=.0253).

There was no consistent evidence that students scored increasingly higher on OSCE stations repeated throughout the year. Thus, it would appear that a clerkship can repeat OSCE stations within an academic year without risk of a trend toward increasing scores.