Canada made a surprise appearance in a CNN health care debate between Senators Bernie Sanders and Ted Cruz on Tuesday night.

Cruz, claiming he knows a lot about Canada because he was born there, said Canadians leave their country in droves to seek out health care in the United States.

This idea is often floated by critics of universal health care on both sides of the border.

But the best-available research shows it’s simply not true. Canadians are not fleeing en masse to the US seeking medical care.

The most comprehensive look at the issue was published in Health Affairs in 2002. Entitled "Phantoms in the Snow," researchers gathered data on Canadians’ use of the US health care system by surveying US border facilities and America’s top-rated hospitals about how often they see Canadians seeking health care. They found this happened rarely.

They also tracked Canadians' behaviors by examining data from the National Population Health Survey, where 18,000 Canadians were asked if they sought medical treatment in the US. "Only 90 of those 18,000 Canadians had received care in the United States; only 20 of them had done so electively."

The Incidental Economist visualized that last point quite nicely:

So, the Health Affairs researchers found no evidence for the idea that Canadians are fleeing their health system, and concluded that it’s a "persistent myth."

One salient reason they offer: Even if Canadians wanted to escape their system, most probably could not afford US medical care. "Prices for U.S. health care services are extraordinarily high, compared with those in all other countries, and this financial barrier is magnified by the extraordinary strength of the U.S. dollar. Private insurance for elective services, being subject to very strong adverse selection, is, not surprisingly, nonexistent."

As the lead author on the paper, University of Michigan's Steven Katz, told Vox, "A hip replacement [in the US] would cost nearly $100,000 out of pocket plus travel and living expenses." Waiting get one for free in Canada is easy compared to that, he added. "Canadians are happier with their system than we are and life expectancy and other health indicators are higher."

H/t to reader Andrew Boozary for tweeting the HA article.