Building on the Evidence Base: Studies on the Effects of Medicaid Expansion, February 2020 to March 2021

Appendix A: Summary Figures, January 2014 – March 2021

The recent studies included in this literature review build on existing research indicating that expansion is linked to gains in coverage; improvements in access, financial security, some measures of health status/outcomes; and economic benefits for states and providers (Appendix Figure 1). This appendix contains updated figures summarizing research on the effects of expansion originally published in an earlier literature review. These figures reflect all 601 included studies on the effects of ACA Medicaid expansion published between January 2014 and March 2021.

Appendix Figure 1: Studies generally find positive effects of the ACA Medicaid expansion on different outcomes.

Study focus over time (Appendix Figure 2). While most early studies focused on expansion’s impact on coverage and economic measures, over time studies have increasingly focused on measures related to access to care.

Appendix Figure 2: More recent studies focus on outcomes related to access.

Coverage (Appendix Figure 3). The full body of research finds positive effects of Medicaid expansion on a range of outcomes related to insurance coverage, including Medicaid coverage gains and reductions in uninsured rates overall and for specific populations. Research suggests limited effects on private coverage rates. Studies also find that expansion has narrowed racial disparities in health coverage for some populations.

Appendix Figure 3: Studies find that the ACA Medicaid expansion had positive effects on insurance coverage, though findings on private coverage are mixed.

Access (Appendix Figure 4). The full body of research finds positive effects of Medicaid expansion on a range of outcomes related to access. In addition to increased access to and utilization of care, studies find that expansion has improved metrics related to quality of care, self-reported health, and health outcomes; provider capacity; and affordability and financial security.

Appendix Figure 4: Studies find that the ACA Medicaid expansion increased access across a range of measures, though findings on health outcomes and provider capacity are mixed.

Economic effects (Appendix Figure 5). Studies find positive effects of Medicaid expansion on a range of economic measures. Economic effects of expansion include improvements in payer mix and other impacts on hospitals and other providers and positive effects on state budgets and economies. Studies also consider Medicaid spending per enrollee, marketplace effects, and employment and labor market effects.

Appendix Figure 5: Studies find positive effects of the ACA Medicaid expansion across a range of economic measures.