Accountable care organizations are comprised of physicians, hospitals and other health care providers who give coordinated care to Medicare patients with the dual goal of increasing quality and lowering costs. The Center for Medicare and Medicaid Innovation was created by the Affordable Care Act partly to test whether ACOs work, and the jury is still out. Controversies also swirl over whether ACOs are instigating consolidation in the health care sector. The government policymakers and industry experts in this session will assess the effectiveness of ACOs, the changes they deem necessary to improve the model and their eventual impact on Medicare and the nation’s health care.