The American College of Cardiology (ACC)/American Heart Association (AHA) clinical performance and quality measure sets serve as vehicles to accelerate translation of scientific evidence into clinical practice. Measure sets developed by the ACC/AHA are intended to provide practitioners and institutions that deliver cardiovascular services with tools to measure the quality of care pro- vided and identify opportunities for improvement. Writing committees are instructed to consider the methodology of clinical performance measure develop- ment (1) and to ensure that the measures developed are aligned with ACC/AHA clinical guidelines. The writing committees also are charged with constructing measures that maximally capture important aspects of care quality, including timeliness, safety, effectiveness, efficiency, equity, and patient-centeredness, while minimizing, when possible, the reporting burden imposed on hospi- tals, practices, and practitioners. Potential challenges from measur...