July 1965: Medicare is signed into law by President Lyndon B. Johnson.
1982: The Tax Equity and Fiscal Responsibility Act imposes limits on provider reimbursement to rein in spending.
1983: The prospective payment system is introduced to pay hospitals a pre-determined rate based on each diagnosis, replacing cost-based reimbursement.
1988: The Medicare Catastrophic Coverage Act is signed into law to provide an outpatient prescription drug benefit and catastrophic coverage for extended hospital stays.
1989: Medicare Catastrophic Coverage Act is repealed, after a huge protest from seniors. The resource-based relative value scale is enacted as a formula to pay physicians.
1997: Balanced Budget Act establishes Medicare Part C, the first managed-care plans to serve beneficiaries, and attempts to slow spending through significant provider pay cuts.
1999: The Balanced Budget Refinement Act is passed into law to ease some of providers' pain caused by the Balanced Budget Act.
December 2003: Medicare Prescription Drug, Improvement and Modernization Act is signed into law, providing a drug benefit, boosting payments to providers and setting the stage for Medicare to compete with private plans.
Sources: CMS, Modern Healthcare reporting