Title (4,000 words exclusive of abstract, acknowledgements, references & figures and tables)

Objectives To examine how the selection of different risk adjustors and statistical approaches affect the profiles of physician groups on patient satisfaction. Data sources Mailed patient surveys. Patients with asthma were selected randomly from each of 20 California physician groups between July 1998 and February 1999. A total of 2,515 patients responded. Study design A cross-sectional study. Patient satisfaction with asthma care was the performance indicator for physician group profiling. Candidate variables for risk-adjustment model building included sociodemographic, clinical characteristics, and self-reported health status. Statistical approaches were the fixed effects vs. the random effects models. Model performance was evaluated using indicators of discrimination (C-index) and calibration (Hosmer-Lemeshow χ). Ranking impact of using different risk adjustors and statistical approaches was based on the changes in absolute and quintile ranking of physician group performance, and the weighted kappa for quintile ranking. Models were also compared to the Consumer Assessment of Health Plans (CAHPS) risk-adjustment model.