Association for Public Policy Analysis & Management

There is evidence that the ACA Medicaid expansion increased insurance coverage and improved access to care for low-income parents, but no published study has focused on the implications for parents who had been eligible for Medicaid prior to the ACA. While newly eligible parents were generally expected to benefit from the expansion, the potential effects for previously eligible parents are more complex. Previously eligible parents may have experienced positive welcome-mat effects if the expansion made them newly aware of their eligibility, but they may also have experienced negative spillover effects on access to care if providers were unable to meet increased demand from the newly insured. In this study, we examine the effects of the Medicaid expansion on insurance coverage and access to care among previously eligible parents.

Methods

We use data from the National Health Interview Survey (2010-2017) and identify previously eligible parents as US citizens with a dependent child and income at the time of the survey below the 2010 parent Medicaid eligibility threshold in their state. We exclude pregnant women and those receiving SSI or Medicare because they face different pathways to Medicaid eligibility. We use a difference-in-differences (DD) analysis to compare changes in outcomes for previously eligible parents in expansion states to those in nonexpansion states. Using nonexpansion states as a counterfactual allows us to isolate the effects of the expansion from other aspects of the ACA that may have affected previously eligible parents. We implement the DD in a regression context controlling for individual demographic and socioeconomic characteristics. Because pre-ACA eligibility thresholds differed across states, our preferred model focuses on 27 states that had parental eligibility thresholds below 70% FPL.

Findings

When we assess impacts for all states, we find no significant effects of the Medicaid expansion for previously eligible parents. When we limit our sample to the 12 expansion states and 15 nonexpansion states that had pre-ACA parental eligibility thresholds below 70% FPL, we find that the expansion increased Medicaid coverage and decreased uninsurance among previously eligible parents which is suggestive of a positive welcome-mat effect. In this sample, however, we also find that the expansion increased delays in care due to a lack of transportation and increased the share of previously eligible parents who reported more than one emergency department visit in the last 12 months. These results could be indicative of access barriers related to the influx of newly insured individuals in expansion states. When we further investigate the timing of these effects, we find that the negative spillover effects on access appear to be concentrated in the early years of the expansion (2014-15), while increases in Medicaid coverage continued into 2016-17.

Conclusions

While there is some evidence of increased barriers to care for very low income previously eligible parents in a subset of states, these effects appear to be temporary while gains in coverage among this population were sustained. This suggests that the long-term effects of the ACA Medicaid expansion on previously eligible parents are likely to be positive.