Medicare is a national social insurance program, administered by the U.S. federal government since 1965 that guarantees access to health insurance for Americans aged 65 and older and younger people with disabilities, as well as people with end stage renal disease and persons with Lou Gehrig’s disease. As a social insurance program, Medicare spreads the financial risk associated with illness across society to protect everyone, and thus has a somewhat different social role from for-profit private insurers, which manage their risk portfolio by adjusting their pricing according to perceived risk.
Medicare offers all enrollees a defined benefit. Hospital care is covered under Part A and outpatient medical services are covered under Part B. To cover the Part A and Part B benefits, Medicare offers a choice between an open-network single payer health care plan (traditional Medicare) and a network plan (Medicare Advantage, or Medicare Part C), where the federal government pays for private health coverage. A majority of Medicare enrollees have traditional Medicare (76 percent) over a Medicare Advantage plan (24 percent) (Medicare.gov, 2012). Medicare Part D covers outpatient prescription drugs exclusively through private plans or through Medicare Advantage plans that offer prescription drugs.