On the face of it, it seems like Medicaid would make people healthier, by giving them access to health care they wouldn't otherwise be able to afford.
But there is a counterargument. It says that being on Medicaid is really worse for you than being uninsured, because it provides you with such low-quality health care.
The debate has raged for decades because every study has lacked a control group. There was no way for researchers to randomly assign people to either receive Medicaid or go without. The Oregon lottery allowed them to do just that.
Katherine Baicker, a professor of health economics at Harvard University, compared those who won the lottery, and those who entered but did not get covered.
Fifty thousand mail surveys and 750 in-person interviews later, they concluded that Medicaid did, in fact, make people healthier.
"People reported their health to be much better once they were insured," Baicker says. "The probability that they reported themselves to be in good, very good or excellent health increased by 25 percent."
People on Medicaid were far less likely to borrow money or have a medical bill sent to a collection agency. And total health care spending (including what is covered by insurance) increased for people on Medicaid.