This document discusses using practice-level clinical data to facilitate transformation to the patient-centered medical home model. It describes a multi-payer initiative in Massachusetts involving 49 practice sites that collected monthly quality measure data over 30 months. The analysis found significantly improved process measures and measures for specific patient populations over time. It concludes that practice transformation takes time, processes of care are more likely to improve before outcomes, and using a clinical quality measure set is important for developing quality improvement skills and evaluating the impact of new practices on patient care.