Standardized patients: a long-station clinical examination format

Data from the first 20 periods of a long-station clinical performance examination for a 4-week required clerkship in family medicine were examined in order to assess the reliability and validity of the examination. Data from 304 students were examined for station, case scenario and examiner effects and results compared to short-station formats. A significant examiner effect was found but there were no differences in student performance for station or case scenario. These findings reflect examiner specificity cited in the literature for short station examinations, but not case specificity. The source of variability for this examination appears to be primarily examiner effect. There was a significant correlation between student scores on the two cases, and raters tended to rank order students similarly in spite of variability in mean rater score. Scores on the CPE correlated with other measures of clinical performance as well as other methods of student evaluation for the clerkship providing some evidence for construct and criterion-related validity. CPE cases were developed from clerkship objectives but examination of the test blueprint revealed some gaps in the extent to which the CPE covers the course content. CPE developers are working to increase interrater reliability through examiner training and further standardize case scenarios through check-lists and patient training. Additional cases are being developed to increase the content validity of the examination.