Comparison of Vignettes, Standardized Patients, and Chart Abstraction
A Prospective Validation Study of 3 Methods for Measuring Quality
- John W. Peabody, MD, PhD;
- Jeff Luck, MBA, PhD;
- Peter Glassman, MBBS, MSc;
- Timothy R. Dresselhaus, MD, MPH;
- Martin Lee, PhD
- Author Affiliations: San Francisco Veterans Affairs Medical Center and Institute for Global Health, University of California, San Francisco (Dr Peabody); RAND, Santa Monica (Dr Peabody); Veterans Affairs, Greater Los Angeles Healthcare System, West Los Angeles (Drs Peabody, Luck, and Glassman); University of California, Los Angeles, Schools of Medicine and Public Health, Los Angeles (Drs Luck, Peabody, and Lee); Veterans Affairs Center for the Study of Health Care Provider Behavior (Drs Peabody, Luck, Lee, and Glassman); and San Diego Veterans Affairs Medical Center, University of California, San Diego School of Medicine (Dr Dresselhaus).
Abstract
Context Better health care quality is a universal goal, yet measuring quality has proven to be difficult and problematic. A central problem has been isolating physician practices from other effects of the health care system.
Objective To validate clinical vignettes as a method for measuring the competence of physicians and the quality of their actual practice.
Design Prospective trial conducted in 1997 comparing 3 methods for measuring the quality of care for 4 common outpatient conditions: (1) structured reports by standardized patients (SPs), trained actors who presented unannounced to physicians' clinics (the gold standard); (2) abstraction of medical records for those same visits; and (3) physicians' responses to clinical vignettes that exactly corresponded to the SPs' presentations.
Setting Outpatient primary care clinics at 2 Veterans Affairs medical centers.
Participants Ninety-eight (97%) of 101 general internal medicine staff physicians, faculty, and second- and third-year residents consented to be randomized for the study. From this group, 10 physicians at each site were randomly selected for inclusion.
Main Outcome Measures A total of 160 quality scores (8 cases × 20 physicians) were generated for each method using identical explicit criteria based on national guidelines and local expert panels. Scores were defined as the percentage of process criteria correctly met and were compared among the 3 methods.
Results The quality of care, as measured by all 3 methods, ranged from 76.2% (SPs) to 71.0% (vignettes) to 65.6% (chart abstraction). Measuring quality using vignettes consistently produced scores closer to the gold standard of SP scores than using chart abstraction. This pattern was robust when the scores were disaggregated by the 4 conditions (P<.001 to <.05), by case complexity (P<.001), by site (P<.001), and by level of physician training (P values from <.001 to <.05). The pattern persisted, although less dominantly, when we assessed the component domains of the clinical encounter—history, physical examination, diagnosis, and treatment. Vignettes were responsive to expected directions of variation in quality between sites and levels of training. The vignette responses did not appear to be sensitive to physicians' having seen an SP presenting with the same case.
Conclusions Our data indicate that quality of health care can be measured in an outpatient setting by using clinical vignettes. Vignettes appear to be a valid and comprehensive method that directly focuses on the process of care provided in actual clinical practice. Vignettes show promise as an inexpensive case-mix adjusted method for measuring the quality of care provided by a group of physicians.
