Medicare, administered by the Centers for Medicare & Medicaid Services (CMS), is the nation’s federal insurance program that pays for covered health services for most persons aged 65 years and older and for most permanently disabled individuals under the age of 65. As a health insurance program, Medicare reimburses health care providers and suppliers, such as hospitals, physicians, and medical equipment companies, for the services and products they provide to Medicare beneficiaries. Medicare is prohibited by law from interfering in the practice of medicine or controlling the manner in which medical services are provided. It also is required to pay for covered services provided to eligible persons so long as specific criteria are met. As such, the growth in per person Medicare expenditures largely reflects the medical practices, use of technology, and underlying costs in the broader health care system. Spending under the program (except for a portion of administrative costs) is considered mandatory spending and is not subject to the appropriations process. Thus, there generally are no limits on annual Medicare spending. Since its enactment in 1965, the Medicare program has undergone considerable change. Because of its rapid growth, both in terms of aggregate dollars and as a share of the federal budget, the Medicare program has been a major focus of deficit reduction legislation passed by Congress. With a few exceptions, reductions in program spending have been achieved largely through freezes or reductions in payments to providers, primarily hospitals and physicians, and by making changes to beneficiary premiums and other cost-sharing requirements. For example, the Patient Protection and Affordable Care Act (ACA; P.L. 111-148 as amended) made numerous changes to the Medicare program that modify provider reimbursements, provide incentives to improve the quality and efficiency of care, and enhance certain Medicare benefits…..