Followup: Medicaid Probably Does Improve Health Outcomes After All

I've now read the new study of the Oregon Medicaid experiment, as well as some additional commentary on it, and I think some of the results are important enough that they deserve a new post, not just updates to the previous post.

In a nutshell, Oregon held a lottery a few years ago in which some people received Medicaid coverage and others didn't. Today's study is a two-year followup, and the headline result is that "Medicaid coverage generated no significant improvements in measured physical health outcomes." But it turns out that "significant" is doing a lot of heavy lifting here, and the headline is extremely misleading.

In fact, the study showed fairly substantial improvements in the percentage of patients with depression, high blood pressure, high cholesterol, and high glycated hemoglobin levels (a marker of diabetes). The problem is that the sample size of the study was fairly small, so the results weren't statistically significant at the 95 percent level.