How Efficient was the Affordable Care Act at Reducing Uninsured Rates? | NBER
Skip to main content
Search
Search
How Efficient was the Affordable Care Act at Reducing Uninsured Rates?
Anuj Gangopadhyaya
& Robert Kaestner
Share
Bluesky
Threads
Link
Working Paper 35263
DOI 10.3386/w35263
Issue Date May 2026
One way to measure the efficiency of the Affordable Care Act (ACA) is the extent to which gains in publicly supported health insurance reduced uninsured rates. Using data from the 2008–2024 American Community Survey, we examine time trends in rates of uninsured, public insurance coverage, and employer-sponsored insurance (ESI) by groups defined by the ratio of income to the Federal Poverty Line (FPL). We obtain estimates of associations between changes in public coverage and changes in uninsured and ESI exploiting state-by-year variation in ACA implementation. Importantly, we estimate the total effect of the ACA—including both the Medicaid expansion and Marketplace coverage—on uninsured and ESI rates. For adults in households below 150% of the federal poverty level (FPL), increases in public insurance coverage were associated with one-for-one decrease in uninsured and no change in ESI. For adults with incomes between 151%–400% FPL, each percentage point increase in public coverage was associated with about a 0.6 percentage point decrease in uninsured and a 0.4 decrease, or crowd out, in ESI. Crowd-out was larger among groups with higher pre-ACA ESI rates such as parents and married adults. Using variation from the Medicaid expansion alone to evaluate the ACA’s effect on ESI leads to overstating crowd-out among low-income adults (below 150% FPL) and understating crowd-out among higher-income adults (above 250% FPL). Our findings suggest that policies intended to subsidize health insurance of higher income groups, for example, the enhanced premium subsidies, are far less efficient than policies intended to further expand public insurance to low-income groups, for example, in non-expansion states.
Acknowledgements and Disclosures
The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.
Citation and Citation Data
Copy Citation
Anuj Gangopadhyaya and Robert Kaestner, "How Efficient was the Affordable Care Act at Reducing Uninsured Rates?," NBER Working Paper 35263 (2026), https://doi.org/10.3386/w35263.
Copy to Clipboard
Download Citation
MARC
RIS
BibTeΧ
Download Citation Data
Related
Topics
Health, Education, and Welfare
Health
Programs
Economics of Health
Public Economics
Working Groups
Insurance
More from the NBER
In addition to working papers, the NBER disseminates affiliates’ latest findings through a range of free periodicals — the NBER Reporter, the NBER Digest, the Bulletin on Health, and the Bulletin on Entrepreneurship — as well as online conference reports, video lectures, and interviews.
2025, 17th Annual Feldstein Lecture, N. Gregory Mankiw," The Fiscal Future"
Feldstein Lecture
Presenter:
N. Gregory Mankiw
N. Gregory Mankiw, Robert M. Beren Professor of Economics at Harvard University, presented the 2025 Martin Feldstein...
2025, Methods Lecture, Raj Chetty and Kosuke Imai, "Uncovering Causal Mechanisms: Mediation Analysis and Surrogate Indices"
Methods Lectures
Presenters:
Raj Chetty
& Kosuke Imai
SlidesBackground materials on mediationImai, Kosuke, Dustin Tingley, and Teppei Yamamoto. (2013). “Experimental Designs...
2025, International Trade and Macroeconomics, "Panel on The Future of the Global Economy"
Panel Discussion
Presenters:
Oleg Itskhoki,
Paul R. Krugman
& Linda Tesar
Supported by the Alfred P. Sloan Foundation grant #G-2023-19633, the Lynde and Harry Bradley Foundation grant #20251294...
Follow
© 2026 National Bureau of Economic Research. All Rights Reserved.