Effects Of The ACA's Health Insurance Marketplaces On The Previously Uninsured: A Quasi-Experimental Analysis

Health Aff (Millwood). 2018 Apr;37(4):591-599. doi: 10.1377/hlthaff.2017.1390.


Descriptive studies have suggested that the Affordable Care Act's (ACA's) health insurance Marketplaces improved access to care. However, no evidence from quasi-experimental studies is available to support these findings. We used longitudinal survey data to compare previously uninsured adults with incomes that made them eligible for subsidized Marketplace coverage (138-400 percent of the federal poverty level) to those who had employer-sponsored insurance before the ACA with incomes in the same range. Among the previously uninsured group, the ACA led to a significant decline in the uninsurance rate, decreased barriers to medical care, increased the use of outpatient services and prescription drugs, and increased diagnoses of hypertension, compared to a control group with stable employer-sponsored insurance. Changes were largest among previously uninsured people with incomes of 138-250 percent of poverty, who were eligible for the ACA's cost-sharing reductions. Our quasi-experimental approach provides rigorous new evidence that the ACA's Marketplaces led to improvements in several important health care outcomes, particularly among low-income adults.

Keywords: Health Economics; Health Reform; Insurance; Insurance Coverage < Insurance; Insurance Market < Insurance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Female
  • Health Insurance Exchanges / statistics & numerical data*
  • Humans
  • Insurance Coverage / statistics & numerical data*
  • Insurance, Health / statistics & numerical data*
  • Longitudinal Studies
  • Male
  • Medically Uninsured / statistics & numerical data*
  • Patient Protection and Affordable Care Act / legislation & jurisprudence*
  • Surveys and Questionnaires