Medicaid is a US government program providing health insurance to low-income individuals and families. It is jointly funded by the federal and state governments but administered primarily at the state level. While states have significant flexibility in designing their programs, the federal government sets minimum standards and provides substantial funding. Though not mandated, all states participate in Medicaid. Eligibility and benefits vary by state, reflecting diverse approaches to healthcare coverage for vulnerable populations.
1927: Section 1927 added to Social Security Act
In 1927, Section 1927 was added to the Social Security Act of 1935 due to the Omnibus Budget Reconciliation Act of 1990 (OBRA-90).
1927: Section 1927 amended by OBRA-93
In 1993, Section 1927 of the Social Security Act was amended by the Omnibus Budget Reconciliation Act of 1993 (OBRA-93), bringing changes to the Medicaid Drug Rebate Program.
1935: Social Security Act
In 1935, the Social Security Act was established, which was later amended to include the Medicaid Drug Rebate Program.
1965: Medicaid Established
In 1965, Medicaid was established as part of President Lyndon B. Johnson's Great Society programs.
1965: Social Security Amendments create Medicaid
The Social Security Amendments of 1965 created Medicaid by adding Title XIX to the Social Security Act.
1973: Rehabilitation Act
Under Section 504 of The Rehabilitation Act of 1973, federal law mandates that children with disabilities receive a "free appropriate public education."
1982: All states participating in Medicaid
As of 1982, all states were participating in Medicaid.
1982: All states participating in Medicaid
By 1982, all states in the United States had chosen to participate in the Medicaid program.
1982: All states participating in Medicaid
By 1982, all states were participating in Medicaid, with Arizona being the last to join.
1990: Omnibus Budget Reconciliation Act of 1990 (OBRA-90)
In 1990, the Omnibus Budget Reconciliation Act of 1990 (OBRA-90) created the Medicaid Drug Rebate Program and the Health Insurance Premium Payment Program (HIPP).
January 1, 1991: Medicaid Drug Rebate Program effective date
On January 1, 1991, the Medicaid Drug Rebate Program became effective after being added as Section 1927 to the Social Security Act of 1935.
1993: Omnibus Budget Reconciliation Act of 1993 (OBRA-93)
In 1993, the Omnibus Budget Reconciliation Act of 1993 (OBRA-93) amended Section 1927 of the Act, changing the Medicaid Drug Rebate Program and requiring states to implement Medicaid estate recovery programs.
2008: Oregon decided to hold a randomized lottery for the provision of Medicaid insurance
In 2008, Oregon decided to hold a randomized lottery for the provision of Medicaid insurance in which 10,000 lower-income people eligible for Medicaid were chosen by a randomized system. The lottery enabled studies to accurately measure the impact of health insurance on an individual's health and eliminate potential selection bias in the population enrolling in Medicaid.
2010: Affordable Care Act Expansion
In 2010, the Affordable Care Act (ACA) significantly expanded Medicaid.
2010: Affordable Care Act Expansion
In 2010, the Affordable Care Act (ACA) significantly expanded the Medicaid program.
2012: Supreme Court allowed states to decide whether to expand Medicaid or not
In 2012, the Supreme Court allowed states to decide whether to expand Medicaid or not, leading to disproportionate expansion in northern states with Democratic legislators.
2012: Supreme Court Decision on Medicaid Expansion
In 2012, the Supreme Court ruled in National Federation of Independent Business v. Sebelius that the federal government could not withdraw all Medicaid funding from states that refused to expand eligibility.
2012: Supreme Court Decision on ACA
In 2012, the Supreme Court ruled that states could maintain pre-ACA Medicaid eligibility standards, leading some states to not expand coverage.
2013: Uninsured Rate in Arkansas
From 2013 to 2015, the uninsured rate in Arkansas dropped from 42% to 14%.
2013: Reimbursement variance in orthopedic procedures
In 2013, there were large variances in reimbursements Medicaid offers to care providers, for example, for common orthopedic procedures, with an average difference of $3,047 in reimbursement for 10 common orthopedic procedures between New Jersey and Delaware.
2013: Affordable Care Act payment increase
One component of the Affordable Care Act was a federally-funded increase in 2013 and 2014 in Medicaid payments to bring them up to 100% of equivalent Medicare payments, in an effort to increase provider participation.
2014: Kaiser Family Foundation Report
A 2014 Kaiser Family Foundation report estimated the national average per capita annual cost of Medicaid services for children, adults, persons with disabilities, aged persons (65+), and all Medicaid enrollees.
2014: Managed Care for Long-Term Care
As of 2014, 26 states contracted with Managed Care Organizations (MCOs) to provide long-term care for the elderly and individuals with disabilities.
2014: Medicaid Expansion Coverage
Beginning in 2014, states participating in Medicaid under the ACA needed to expand coverage to individuals earning up to 138% of the Federal poverty level.
2014: Affordable Care Act payment increase
One component of the Affordable Care Act was a federally-funded increase in 2013 and 2014 in Medicaid payments to bring them up to 100% of equivalent Medicare payments, in an effort to increase provider participation.
October 2015: Kaiser Family Foundation Estimate
In October 2015, the Kaiser Family Foundation estimated that 3.1 million additional people were not covered in states that rejected the Medicaid expansion.
2015: Uninsured Rate in Kentucky
From 2013 to 2015, the uninsured rate in Kentucky dropped from 40% to 9%.
2016: DHHS study on Medicaid expansion and premiums
A 2016 DHHS study found that states that expanded Medicaid had lower premiums on exchange policies because they had fewer low-income enrollees.
2016: Uninsured rates in Medicaid expansion vs. non-expansion states
In the first quarter of 2016, states that expanded Medicaid had an uninsured rate of 7.3% among adults aged 18 to 64, while non-expansion states had a 14.1% uninsured rate.
2017: Medicaid enrollment increases political participation
A 2017 study found that Medicaid enrollment increases political participation, measured in terms of voter registration and turnout.
2017: Medicaid improved recipients' health and financial security
In 2017, a survey of academic research indicated that Medicaid improved recipients' health and financial security, while expansion was linked to increases in employment and student status. A paper also found that Medicaid expansion under the Affordable Care Act reduced unpaid medical bills sent to collection by $3.4 billion in its first two years, preventing new delinquencies and improving credit scores.
2018: Uninsured Rate in Expansion vs. Non-Expansion States
In 2018, the uninsured rate for adults between 100% and 399% of the poverty level was 12.7% in Medicaid expansion states and 21.2% in non-expansion states.
July 2019: NBER Study on Mortality Rates
A July 2019 study by the National Bureau of Economic Research (NBER) indicated that states enacting Medicaid expansion exhibited statistically significant reductions in mortality rates.
September 2019: Census Bureau Report on Uninsured Rates
In September 2019, the Census Bureau reported that states that expanded Medicaid under the ACA had considerably lower uninsured rates than states that did not.
2019: Medicaid Funding for Births
In 2019, Medicaid paid for half of all U.S. births.
2020: State contribution to Medicaid expansion
By 2020, states were required to pay for 10% of the costs associated with the newly covered population under the ACA Medicaid expansion.
2020: Long-term services and supports
In 2020, about 5.6 million of the 7.7 million Americans who used long-term services and supports were covered by Medicaid.
2020: State contribution to Medicaid expansion
Several states argued that they could not afford the 10% contribution in 2020 for Medicaid expansion costs.
2021: Medicaid expansion in Louisiana led to reductions in medical debt
In 2021, a study in the American Journal of Public Health found that Medicaid expansion in Louisiana led to reductions in medical debt.
2021: Average cost per enrollee
In 2021, the average cost per Medicaid enrollee was $7,600.
2022: Medicaid eligibility during childhood reduced the likelihood of criminality during early adulthood
A 2022 study found that Medicaid eligibility during childhood reduced the likelihood of criminality during early adulthood.
2022: Medicaid provides coverage to 85 million people
As of 2022, Medicaid provided free health insurance to 85 million low-income and disabled people in the United States.
March 2023: Medicaid Expansion Acceptance
As of March 2023, 40 states and the District of Columbia had accepted the Affordable Care Act Medicaid expansion, while 10 states had not.
2023: Total cost of Medicaid
In 2023, the total annual cost of Medicaid (federal and state) was $870 billion.
2025: Proposed Medicaid Cuts
During 2025, Republican Congressional leaders and President Donald Trump discussed and proposed various cuts to Medicaid, including lowering the federal matching rate and requiring employment for eligibility.