The Congressional Budget Office estimates that by 2019, ObamaCare will cover 32 million U.S. residents who would otherwise have been uninsured. Half of those coverage gains would come from expanding the Medicaid program, which has been criticized for poor-quality care.

A new study in the journal Inquiry gives another indication that Medicaid provides low-quality care:

we find that uninsured and Medicaid patients are treated by lower-quality physicians both because of the hospitals these patients attend and because of sorting within hospitals…Our study concluded that patients in government hospitals that treat large numbers of uninsured and Medicaid patients are least likely to be treated by a board-certified or top-trained physician.

The study has plenty of limitations. For one, physician training is an input, not an output. What matters are health outcomes, and so it will be interesting to see what the Oregon Health Study has to say about Medicaid’s effects on health.