Using standardized patients to measure quality: evidence from the literature and a prospective study.

Background: Use of standardized patients for evaluating the clinical skills of medical students and medical trainees is commonplace. This has encouraged the use of standardized patients to evaluate the quality of physician practice in outpatient settings. However, there may be substantive differences between observing student performance and evaluating whether the provision of care meets defined quality criteria.

Objectives: This study had two primary objectives: (1) to review studies that use standardized patients to evaluate physician performance and (2) to ascertain directly whether standardized patients could be useful in assessing quality of outpatient care.

Methods: A comprehensive literature review of studies that used standardized patients to assess physician performance was conducted. A prospective study that included 20 physicians at two outpatient settings and 27 actor patients assessed quality of care using eight clinical cases divided into five clinical domains, each of which had explicit criteria checklists based on widely accepted guidelines.

Results: The literature review identified five important issues: developing scenarios, selecting explicit criteria, standardizing standardized patient training, creating subterfuges, and ensuring reliability and validity of measures. In the study, trained standardized patients were able to assess physician practice accurately for common medical conditions, using proven criteria linked to health outcomes. The detection rate was 3%. There was no performance variation between actors for seven of the eight cases.

Conclusions: Using standardized patients to measure the quality of care is practical and feasible. The major methodological challenge is incorporating observable evidence-based criteria into realistic scripts and objective checklists. The major logistical challenge is obtaining and maintaining undetected entry into physicians' offices.