The Effects of ACA Medicaid Expansions on Health After 5 Years.

We examine the Affordable Care Act Medicaid expansion effects on self-rated health status over 5 years. The study uses data from the Behavioral Risk Factor Surveillance System for 2011-2018 and a difference-in-differences design. There is improvement in health status on a 1 to 5 point scale from poor to excellent health among individuals below 100% of the federal poverty line by 0.031, 0.068, 0.031, 0.064, and 0.087 points in 2014, 2015, 2016, 2017, and 2018, respectively. Changes in 2015, 2017, and 2018 are statistically significant (p < .05), and the 2014 change is marginally significant. The difference between 2014 and 2018 effects is statistically significant (p < .05). In most years, we cannot distinguish changes in days not in good physical or mental health from no effect. Overall, there is only minimal evidence for effects intensifying over time, suggesting that health gains thus far have mostly occurred early on due to unmet needs among those previously uninsured.