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The Affordable Care Act at 10 Years: What’s the Effect on Health Care Coverage and Access?


The Issue

It’s been 10 years since the passage of the Affordable Care Act (ACA) — one of the most important and controversial pieces of health care legislation in U.S. history. In the first of two health policy reports for the New England Journal of Medicine, the Commonwealth Fund’s David Blumenthal, M.D., Sara Collins, and Elizabeth Fowler looked back at the ACA’s evolution, accomplishments, and shortfalls, focusing on the ACA’s federal subsidies and individual insurance market reforms designed to increase the number of people with affordable, high-quality insurance. A second report examined the ACA’s reform to the U.S. health care delivery system.

The ACA has reduced the number of uninsured people to historically low levels and helped more people access health care services, especially low-income people and people of color.

What the Report Found

  • Coverage. By 2016, the number of people without health insurance had decreased to a low of 28.6 million but has since ticked up. New enrollment, largely resulting from the expansion in Medicaid eligibility, drove more than 50 percent of coverage gains. Enrollment through ACA marketplaces accounted for nearly half of insurance coverage gains, helped in large part by premium assistance. In addition, the dependent-coverage provision of the ACA helped decrease the percentage of young adults who are uninsured.
  • Congressional and administration actions. Actions by the Republican-led Congress and executive branch following the 2016 election reversed some of the ACA’s coverage gains. However, many key provisions of the law — Medicaid expansion, marketplace subsidies, and market reforms — remained intact after Congress failed to repeal the ACA in 2017.
  • Costs to the federal government. Medicaid expansion, along with marketplace subsidies and reforms, cost the federal government $128 billion in 2019 — considerably less than the $172 originally projected. Lower growth in health care costs generally, lower premiums in the marketplaces, and lower enrollment in the marketplaces are the primary reasons.
  • Access to care. Growth in the number of people with health insurance is associated with improved access to care and greater use of health services. Use of primary and specialty care services and prescription drug access are higher among low-income adults in states that expanded Medicaid.
  • Financial protection. Medicaid expansion, marketplace subsidies, and the ACA’s dependent-coverage provision have decreased out-of-pocket health costs among enrolled persons.
  • Effects on health. The law’s effects on health are more mixed and will require additional study. However, Medicaid expansion has been associated with reductions in deaths from cardiovascular-related causes among middle-aged adults and in deaths from end-stage renal disease.

The Big Picture

The ACA has reduced the number of uninsured people to historically low levels and helped more people access health care services, especially low-income people and people of color. However, the law’s effects on the cost and quality of health care services are difficult to discern given the complexity of our health system.

The ACA’s implementation has taken major unexpected twists and turns, especially with respect to the law’s coverage and access provisions. Partisan conflict has stymied subsequent efforts by Congress to make improvements to the ACA. Meanwhile, states have had considerable discretion in how the ACA is implemented, creating variability in how the law has affected people across the country.

Efforts to roll back key provisions of the ACA or invalidate it are taking a toll. If the Supreme Court rules the ACA unconstitutional, it will substantially disrupt the U.S. health system and could eliminate insurance coverage for millions of Americans.

The Bottom Line

The ACA has reduced the percentage of uninsured Americans to historically low levels, but its future remains uncertain.

Publication Details



Bethanne Fox, Vice President, Outreach and Strategy, The Commonwealth Fund

[email protected]


David Blumenthal, Sara R. Collins, and Elizabeth J. Fowler, “The Affordable Care Act at 10 Years — Its Coverage and Access Provisions,” New England Journal of Medicine, published online Feb. 26, 2020.