QRS led a team comprised of The Johns Hopkins School of Public Health, NORC at the University of Chicago, and Noblis in assessing the CMS ACO program. The objective of the effort was the development of quality measures for assessing ACO performance. The team performed an extensive review of the quality literature, refined the hundreds of potential measures to a meaningful subset, and delivered some 30 fully developed measures to CMS. The development process included conducting an environmental scan, interacting with measure stewards, testing select measures with extensive patient data, preparing implementation software and guidelines, specifying acceptable measure outcomes, and reporting the results to CMS. The measures focused on inpatient care as well as on diagnoses resulting in avoidable ambulatory admissions and readmissions within 30 days of discharge.