Accountable care organizations (ACOs) have proliferated under the Affordable Care Act (ACA). If ACOs are to improve health care quality and lower costs, quality measures will be increasingly important in determining if provider consolidations associated with the development of ACOs are achieving their intended purpose. This article assesses quality measurement across public and private sectors. We reviewed available quality measures for a subset of programs in six organizations and assessed the number and domain of measures (structure, process, outcomes, and patient experience). Two-thirds of all quality measures were categorized as process measures. Outcome measures made up nearly 20 percent of measures. Patient experience and structure measures made up approximately 8 percent and 7 percent, respectively. We propose further improvements to quality measurement initiatives. For example, programs that reward providers should consider reward size and distribution within the organization. Quality improvement initiatives should consider what encourages provider buy-in and participation and the effects on populations with disproportionate health care needs. As the focus of quality initiatives may change from year to year, measures should be periodically revisited to ensure continued improvement and sustainability. Finally, we suggest quality measures that regulators could use prior to ACO formation or in the year or two following formation.