Standardized patients (SPs) are being used with increasing frequency to teach and assess clinical skills at many U.S. and Canadian medical schools. National organizations responsible for the licensure and certification of physicians have recently undertaken large pilot projects to determine the merits of this method of performance-based assessment. These assessments typically use a multi-station examination where examinees move from room to room and examine SPs who simulate a variety of health complaints. There may also be non-patient-based stations where the examinees interpret X-rays, diagnostic studies, videotapes, and so forth. The study reported here is part of a project conducted by the Educational Commission for Foreign Medical Graduates (ECFMG), which uses SPs at multiple test sites to assess graduates of foreign medical schools.