The Effect of ACA Medicaid Expansions for Adults on Insurance Coverage for Low-Income Children
This paper investigates the potential for “welcome mat” effects under the ACA. In particular, we observe publicly eligible children and measure the impact of Medicaid expansions for adults on the probability that a child enrolls in public coverage. Using data from 2013 and 2014, we take advantage of the natural experiment created by the Supreme Court decision that allowed states to choose whether or not to expand Medicaid to adults. We use a difference-in-differences model to compare changes in eligible children’s coverage between 2013 and 2014 in Expansion-states vs. Nonexpansion-states.
We use the data from the American Community Survey (ACS) conducted by the U.S. Census Bureau. The ACS is currently the largest household survey in the U.S., and draws a sample of three million U.S. addresses per year. In 2014, the ACS public use sample included 708,121 children. The ACS contains rich information on demographic, socioeconomic, geographic, and health characteristics, including income, citizenship, disability, and health insurance coverage. The information enables us to determine the eligibility of Medicaid (and CHIP) and the types of insurance coverage held for both children and their parents.
Preliminary results suggest the presence of welcome mat effects of the ACA. Sample means for children in families with income below 138% FPL using ACS data show the increase in the probability of public coverage for all children in 2014 compared to 2013, and that this increase was twice as large in states that expanded coverage to adults than in states that did not.