Who's Driving Medicaid's Enrollment Growth?

Since 1990, Medicaid outlays per capita have increased fourfold, driven primarily by enrollment growth rather than rising costs per enrollee. The program, which has served since its inception as a safety net for the elderly, the disabled, and children living in poverty, has grown over time; in 2024, more than one in four Americans was enrolled. With new community engagement requirements poised to reshape the program, understanding what demographics are driving Medicaid's enrollment growth can provide insights into how the program is likely to evolve going forward. We show that children and their families drove growth from 1990 to 2000; childless adults, both working and nonworking, drove growth from 2000 to 2013; and all working adults drove growth from 2013 to 2024.