Newly and Previously Eligible Medicaid Enrollees Differ, but Not in Health Care Expenditures.

In 2014, the Affordable Care Act (ACA) expanded the role of Medicaid by encouraging states to increase eligibility for lower-income adults. As of 2024, 10 states had not adopted the expanded eligibility provisions of the ACA, possibly due to concerns about the state's share of spending. Using the Medical Expenditure Panel Survey (MEPS), we documented how health care utilization, expenditures, and the overall health status of newly eligible enrollees compare with enrollees who would have been eligible under their states' rules before the ACA. Our estimates suggest that, during 2014-16, newly eligible Medicaid enrollees had worse health and greater utilization and expenditures than previously eligible enrollees. However, during 2017-19, newly and previously eligible enrollees had comparable per capita health expenditures across six types of health spending. We find some evidence that changes in Medicaid enrollment composition muted observed differences between eligibility groups.