The Impact of the ACA Medicaid Expansions on Health Insurance Coverage through 2015 and Coverage Disparities by Age, Race/Ethnicity, and Gender.

OBJECTIVE: Examine the ACA Medicaid expansion effects on Medicaid take-up and private coverage through 2015 and coverage disparities by age, race/ethnicity, and gender.

DATA SOURCES: 2011-2015 American Community Survey for 3,137,989 low-educated adults aged 19-64 years.

STUDY DESIGN: Difference-in-differences regressions accounting for national coverage trends and state fixed effects.

PRINCIPAL FINDINGS: Expansion effects doubled in 2015 among low-educated adults, with a nearly 8 percentage-point increase in Medicaid take-up and 6 percentage-point decline in uninsured rate. Significant coverage gains were observed across virtually all examined groups by age, gender, and race/ethnicity. Take-up and insurance declines were strongest among younger adults and were generally close by gender and race/ethnicity. Despite the increased take-up however, coverage disparities remained sizeable, especially for young adults and Hispanics who had declining but still high uninsured rates in 2015. There was some evidence of private coverage crowd-out in certain subgroups, particularly among young adults aged 19-26 years and women, including in both individually purchased and employer-sponsored coverage.

CONCLUSIONS: The ACA Medicaid expansions have continued to increase coverage in 2015 across the entire population of low-educated adults and have reduced age disparities in coverage. However, there is still a need for interventions that target eligible young and Hispanic adults.