The Impact of the Affordable Care Act Medicaid Expansion on Insurance Status and Type of Coverage for Non-Disabled Childless Adults in Poverty
We find that expanding Medicaid to non-disabled childless adults in poverty reduced uninsurance among this group by 14.9 percentage points (35.5% of the 2013 uninsurance rate) in states where they were previously ineligible compared to observably similar adults in non-expansion states. This decrease in uninsurance was driven primarily by a 15.4 percentage point increase in Medicaid coverage. Our estimates of the marginal take-up rate are substantially higher than is typical in the literature, suggesting that administrative changes in enrollment, response to the individual mandate, and public awareness of the ACA may have led to higher take-up than usual. The 2014 Medicaid expansion had no impact on private insurance coverage in our population of interest, suggesting that "crowd-out" of private coverage was limited in 2014. These findings are robust to controls for differential pre-ACA trends in coverage in expansion and non-expansion states.
In subgroup analyses, we find that men in the target population were eight percentage points less likely than women to gain insurance coverage, and that this gender difference was driven entirely by differences in Medicaid take-up. We also found dramatically higher Medicaid take-up among adults over age 35 (by 10-20 percentage points) relative to younger adults, and among those in fair or poor health (by 19 percentage points) relative to healthier adults.
These findings suggest that the ACA’s Medicaid expansion successfully increased the number of insured individuals, and that those with the greatest health need (e.g. older adults, those in fair or poor health) were most likely to take-up coverage in response to the expansion. Further, we find no evidence of crowd-out of employer coverage among this population, implying that—at least in 2014—expanding Medicaid to low-income childless adults effectively targeted previously uninsured individuals.