Misclassification Risk of Tier-Based Physician Quality Performance Systems

OBJECTIVE: There is increasing interest in identifying high-quality physicians, such as whether physicians perform above or below a threshold level. To evaluate whether current methods accurately distinguish above- versus below-threshold physicians, we estimate misclassification rates for two-category identification systems. DATA SOURCES: Claims data for Medicare fee-for-service beneficiaries residing in Florida or New York in 2010. STUDY DESIGN: Estimate colorectal cancer, glaucoma, and diabetes quality scores for 23,085 physicians. Use a beta-binomial model to estimate physician score reliabilities. Compute the proportion of physicians whose performance tier would be misclassified under three scoring systems. PRINCIPAL FINDINGS: In the three scoring systems, misclassification ranges were 8.6-25.7 percent, 6.4-22.8 percent, and 4.5-21.7%. True positive rate ranges were 72.9-97.0 percent, 83.4-100.0 percent, and 34.7-88.2 percent. True negative rate ranges were 68.5-91.6 percent, 10.5-92.4 percent, and 81.1-99.9 percent. Positive predictive value ranges were 70.5-91.6 percent, 77.0-97.3 percent, and 55.2-99.1 percent. CONCLUSIONS: Current methods for profiling physicians on quality may produce misleading results, as the number of eligible events is typically small. Misclassification is a policy-relevant measure of the potential impact of tiering on providers, payers, and patients. Quantifying misclassification rates should inform the construction of high-performance networks and quality improvement initiatives.