Expanding Medicaid Research Beyond Medicaid Expansion

By Joseph Benitez, PhD
May 28, 2021

Joseph Benitez is a health services researcher, health economist and assistant professor in the Department of Health Management and Policy at the University of Kentucky, as well as a member of the 2021 Tradeoffs Research Council. His research interests include the impacts of public policy changes on the medically underserved, Medicaid policy and the role of Medicaid as a safety-net program.

As we await another Supreme Court decision about the fate of the Affordable Care Act (ACA), it’s worth remembering that the high court’s greatest impact (so far) on the health law was likely its 2012 decision making Medicaid expansion optional. To date, 38 states and Washington, D.C. have expanded, while 12 states have not. This unintended natural experiment has allowed researchers to compare expansion and non-expansion states from almost every angle, resulting in an overwhelming literature covering the implications and impacts of Medicaid expansion

However, expansion is not the only difference between state Medicaid programs — states can, for example, establish different requirements for who is eligible, what benefits they can receive and how hard it is for people to get and stay enrolled. These differences have been explored much less in empirical research, and knowing how these policies interact with one another can better inform policymakers on Medicaid’s functions and how it can best serve the people who need it. In a November 2020 study in Health Affairs, researchers Ashley M. Fox, Wenhui Feng, Jennifer Zeitlin and Elizabeth A. Howell sought to begin to fill this gap.

The authors developed index scores (0 to 100) summarizing the different choices all 50 states and the District of Columbia have in designing four elements of their Medicaid programs — income eligibility guidelines, administrative burden (how easy or hard it is to enroll or stay enrolled), eligibility for low-income immigrants and benefit comprehensiveness. Lower scores meant states were less generous and more restrictive, while higher scores meant they used more tools available to maximize who was eligible (including immigrants), ease administrative burdens and offer more comprehensive health benefits (for example dental coverage). The authors then compared states’ scores on each metric for each year from 2000 to 2018 (the years included vary slightly for each metric).

Unsurprisingly, the authors found that expansion states scored higher on all four metrics compared to non-expansion states. However, they also found that across almost all states (expansion and non-expansion), non-immigrant eligibility and ease of administrative burden faced by enrollees have been trending upward, while benefits and immigrant eligibility have stayed relatively flat. The fact that enrollment got easier, for example, in both Kentucky (expansion state) and neighboring Tennessee (non-expansion state) is a testament to the broader impact the ACA has had nationwide in streamlining access to both public and private health coverage. 

In addition to this study, the authors are sharing the dataset they compiled comparing Medicaid policies across states from 2000 to 2020. This database is a treasure trove to Medicaid researchers and will provide a way to better shape evidence-based policymaking around Medicaid — a program that accounts for roughly 1/3 of most states’ budgets and covers 1 in 5 Americans.

Moving beyond single-dimension analyses of Medicaid like expansion vs. non-expansion will provide more context-specific insights for Medicaid research. It will allow researchers to apply a comparative effectiveness framework, facilitating more nuanced comparisons of Medicaid program performance across states and better helping policymakers understand how multiple Medicaid policy levers can be used together to get the most out of this important program.

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