This paper draws on the experiences under Massachusetts’s 2006 health reform, the template for the Affordable Care Act (ACA), to provide insights into the potential impacts of the ACA Medicaid expansion for low-income childless adults in other states. The study takes advantage of the natural experiment in Massachusetts and combines data from two surveys—the Massachusetts Health Reform Survey (MHRS) and the National Health Interview Survey (NHIS)—to estimate the impacts of reform on low-income adults. The MHRS provides a relatively large sample for the state of Massachusetts, the NHIS provides data for samples in other states, and county-level economic and health care market characteristics are provided by the Area Health Resource File (AHRF). To estimate the impact of health reform on low-income childless adults, we use difference-in-differences models with propensity-score reweighting to improve the match between Massachusetts and our comparison states. Results suggest large gains in health care coverage for low-income adults in Massachusetts, particularly for the low-income childless population, with estimates ranging from 18 to 24 percentage point increases, depending on the comparison group. Additionally, health reform provided greater access to the health care system for low-income childless adults, reflected in our finding of 10 to 19 percentage point increases in having a usual source of care.

As part of the ACA, states were given the option to expand Medicaid eligibility tor nearly all nonelderly adults up to 138 percent of the FPL under Medicaid as part of the ACA. The largest component of this expansion population is childless adults, as they have not been eligible for Medicaid coverage in most states heretofore. Massachusetts included an expansion of coverage under the Commonwealth Care program, a Medicaid-like program, to low-income childless adults as part of its 2006 health reform initiative. Massachusetts’ reform effort also included many other elements that were incorporated into the ACA, including a health insurance exchange, dependent coverage expansion and an individual mandate for insurance coverage.

While the impacts of the ACA will vary across the states given the differences in their health care systems and policies in place prior to reform, the differences in their choices under reform, and their very different policy and economic environments, the findings from Massachusetts' 2006 reform highlight the potential for significant gains for low-income childless adults under the ACA. The evidence from this analysis, which combines data from a state survey with national survey data to support an evaluation that is not possible with either survey alone, suggests a strong response by low-income childless adults under health reform in states that expand Medicaid eligibility. For states that implement the Medicaid provisions of the ACA, we would expect to see large increases in coverage rates and commensurate gains in access to health care for low-income childless adults. These estimates provide preliminary information on the potential gains under the ACA for states that have expanded Medicaid eligibility and the potential losses for states that choose not to expand Medicaid.