Descriptive studies have suggested that the Affordable Care Act’s (ACA) health insurance Marketplaces improved access to care. However, no quasi-experimental evidence is currently available to support these findings. We use longitudinal survey data to compare previously- uninsured adults to adults who had employer-sponsored insurance (ESI) prior to the ACA, in the income range eligible for subsidized Marketplace coverage (138-400% of poverty). Among the previously-uninsured group, the ACA led to a significant decline in the uninsurance rate (-10.8 percentage points), decreased barriers to medical care, increased use of outpatient services and prescriptions drugs, and increased identification of high blood pressure, compared to a control group with stable ESI. Changes were largest among those with incomes between 138-250% 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 lower-income adults.
