Expanding coverage to low-income childless adults in Massachusetts: implications for national health reform.

OBJECTIVE: To draw on the experiences under Massachusetts's 2006 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.

DATA SOURCES/STUDY SETTING: The study takes advantage of the natural experiment in Massachusetts and combined 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.

STUDY DESIGN: Difference-in-differences models of the impacts of health reform, using propensity-score reweighting to improve the match between Massachusetts and the comparison states.

DATA COLLECTION/EXTRACTION METHODS: Data for low-income adults are obtained by combining data from the MHRS and the NHIS, where the MHRS provides a relatively large Massachusetts sample and the NHIS provides data for samples in other states to support the difference-in-differences model. Supplemental data on county economic and health care market characteristics are obtained from the Area Health Resource File.

PRINCIPAL FINDINGS: There are strong increases in coverage and access to health care for low-income adults under health reform in Massachusetts, with the greatest gains observed for childless adults, who were not eligible for public coverage prior to reform.

CONCLUSIONS: In the 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 care for low-income childless adults. Linking state and federal surveys offers a strategy for leveraging the value of state-specific survey data for stronger policy evaluations.