More than four years after the implementation of the Medicaid expansion included in the Affordable Care Act, debate and controversy around the implications of the expansion continue. Despite a large body of research that shows that the Medicaid expansion results in gains in coverage, improvements in access and financial security, and economic benefits for states and providers, some argue that the Medicaid expansion has broadened the program beyond its original intent diverting spending from the “truly needy”, offers poor quality and limited access to providers, and has increased state costs. New proposals allow states to implement policies never approved before including conditioning Medicaid eligibility on work or community engagement. New complex requirements run counter to the post-ACA movement of Medicaid integration with other health programs and streamlined enrollment processes. This brief examines evidence of the effects of the Medicaid expansion and some changes being implemented through waivers. Many of the findings on the effects of expansion cited in this brief are drawn from the 202 studies included in our comprehensive literature review that includes additional citations on coverage, access, and economic effects of the Medicaid expansion.