Public Health Insurance Expansions and the Uniformity of Insurance for Families

While traditional private insurance tends to be offered to either individuals or whole families (with no child-only options), public insurance eligibility is determined person-by-person.  In each state, the income eligibility thresholds for public coverage can differ for parents and children, and at times even among children in different age groups.  Often, public insurance eligibility is more generous for children than their parents, with the widest accessibility for the youngest children.  Having different insurance sources, or a mix of insured and uninsured members of a family, may be disruptive to consistent medical care.  In this paper we investigate the extent to which differential eligibility thresholds for public insurance for children and adults, and changes in these thresholds, are associated with mismatched patterns of insurance coverage.  Using the Current Population Survey in 1988-2013, we document the patterns of insurance mismatch over time and their relationship to Medicaid and State Children’s Health Insurance Program income eligibility thresholds.  We find that changes in parent thresholds can promote uniform insurance coverage for families – though these expansions do lead to some crowd-out of private insurance for adults. These results are driven by families led by single mothers, who are more likely to be affected by Medicaid expansions for parents.  We then use the longitudinal Survey of Income and Program Participation (1996-2013) to gain further insight into the dynamics of how changing eligibility for parents or children may drive changes in decisions about insurance, resulting in changes in their uniformity of coverage.  This work raises important questions about possible unintended consequences of a person-level approach to public insurance eligibility.