Who should rate candidates in an objective structured clinical examination?

PURPOSE: To determine who is the better rater of history taking in an objective structured clinical examination (OSCE): a physician or a standardized patient (SP). METHOD: During the 1991 pilot administration of an OSCE for the Medical Council of Canada's qualifying examination, five history-taking stations were videotaped. Candidates at these stations were scored by three raters: a physician (MD), an SP observer (SPO), and an SP rating from recall (SPR). To determine the validity of each rater's scores, these scores were compared with a "gold standard", which was the average of videotape ratings by three physicians, each scoring independently. Analysis included both correlations with the standard and a repeated-measures analysis of variance (ANOVA) comparing raters' mean scores on each station with mean scores of the gold standard. RESULTS: Ninety-one videotapes were scored by the "gold-standard" physicians. Correlations with the standard showed no clear preference for MD, SPO, or SPR raters. ANOVAs revealed significant differences from the standard on three stations for the SPR, two stations for the SPO, and one stations for the MD. CONCLUSIONS: An MD rater is less likely to differ from a standard established by a consensus of MD ratings than are SP raters rating from recall. If an MD cannot be used, an SP observer is preferable to an SP rating from recall.