The evolving science of quality measurement for hospitals: implications for studies of competition and consolidation.

The literature on hospital competition and quality is young; most empirical studies have focused on few conditions and outcomes. Measures of in-hospital mortality and complications are susceptible to bias from unmeasured severity and transfer/discharge practices. Only one research team has evaluated related process and outcome measures, and none has exploited chart-review or patient survey-based data. Prior studies have generated inconsistent findings, suggesting the need for additional research. We describe the strengths and limitations of various approaches to quality measurement, summarize how quality has been operationalized in studies of hospital competition, outline three mechanisms by which competition may affect hospital quality, and propose measures appropriate for testing each mechanism.