Medicaid expansions and private insurance “crowd-out” (1999–2019)
Document Type
Article
Abstract
Background: Recent Medicaid expansions have rekindled the debate around private insurance “crowd-out.” Prior research is limited by short-time horizons and state-specific analyses. Our study overcomes these limitations by evaluating 20 years of Medicaid expansions across the entire United States. Methods: We obtain data from the U.S. Census Bureau for all U.S. states and District of Columbia for private insurance coverage rates of adults 18–64 for years 1999–2019. After estimating a naïve, staggered Two-way fixed effects difference-in-differences regression model, we implement four novel econometric methods to diagnose and overcome threats of bias from staggered designs. We also test for pre-treatment differential trends and heterogenous effects over time. Results: Our findings suggest that Medicaid expansion was associated with a 1.5 percent-point decline in private insurance rates (p < 0.001). We also observe significant heterogeneity over time, with estimates peaking 4 years after expansion. Conclusions: Medicaid expansions reduced private insurance rates. Future research should assess whether or how this crowd-out may have affected consumer welfare or government budgets. Recognizing the crowd-out should enable policymakers to make informed decisions regarding healthcare policy. The importance of a 1-2 percent-point crowd-out, we leave for future research and debate.
DOI
10.1111/ssqu.13318
Publication Date
12-1-2023
Recommended Citation
Semprini, Jason, "Medicaid expansions and private insurance “crowd-out” (1999–2019)" (2023). Public Health. 20.
https://digitalcommons.dmu.edu/fac_ph/20
