Quality measures are a way to hold providers and healthcare payers (private insurance companies as well as the Medicare program) accountable for delivering efficient, evidence-based, high-quality, and cost-effective care. The Healthcare Effectiveness Data and Information Set (HEDIS®) is a set of performance measures used widely in managed care. The measures are developed and maintained by the National Committee for Quality Assurance (NCQA). HEDIS was designed to compare health plan performance relative to national benchmarks. Inovalon evaluated how different types of insurance plans perform on a set of 5 widely used quality measures using claims data from commercial, Medicare, and Medicaid insurance plans. The measures assess a range of service and outcome-based issues that are important to achieving high-quality care, including access to care, use of preventive screenings and test, use of evidence-based treatments, and hospital readmissions.