Medicaid Expansion Coverage Effects Grew In 2015 With Continued Improvements In Coverage Quality

Previous research has demonstrated large gains in insurance coverage associated with the Affordable Care Act's (ACA's) Medicaid expansion in 2014. We used detailed federal survey data through 2015 to analyze more recent changes in coverage for low-income adults after the expansion. We found that the uninsurance rate fell in both expansion and nonexpansion states but that it fell significantly more in expansion states. By 2015 the post-ACA uninsurance rate for low-income adults had fallen by 7.5 percentage points more in expansion than in nonexpansion states, a difference that was similar (about 6.8 percentage points) in adjusted regression models. Private coverage increased in nonexpansion states, but significantly less than Medicaid coverage increased in expansion states. Rates of private coverage did not appear to decline in expansion states. Finally, Medicaid expansion was associated with significantly improved quality of health coverage, as reported by low-income adults.