Medicaid is a welfare program jointly funded by federal and state governments, which claims to provide health insurance to low income people. A few years ago, Oregon expanded Medicaid enrollment by lottery. This created an excellent environment to study the effects of being uninsured versus being enrolled in Medicaid, because it approximated a randomized-controlled trial — the gold standard of medical research, but seldom conducted in the social sciences.
This result is important for anticipating the consequences of ObamaCare. About half of the 30-plus million people expected to get health insurance under ObamaCare will be enrolled in Medicaid, not private health insurance. Already, the Administration asserts that four million new Medicaid enrollees have signed up via ObamaCare (but this estimate has been questioned).