Research on gasoline markets has likewise found that publicizing prices appears to enable collusion in places where there are only a few competitors. But among more plentiful Israeli supermarkets, a database of prices appears to have lowered them.

Scholars at the Federal Trade Commission put out a paper in 2015 cautioning against the kind of price transparency that the president is embracing. Guess what paper showed up in the footnotes?

But it’s not clear how similar Danish ready-mix concrete in the 1990s is to American health care today. The voices arguing for greater price transparency note that the most-cited studies come from pretty far afield.

And many other markets in the U.S. economy do seem to benefit from clear information about prices. Most Americans wouldn’t buy a car — or even an oil change — without knowing the cost. The question is whether the transparency will be more useful to hospitals or to consumers. If you think the answer is consumers, you think transparency will lower prices.

“I don’t know if they think that’s too obvious, or it sounds too high school, and they have a Ph.D,” said Katy Talento, a health care consultant who worked on the transparency policy while she was the top health policy adviser in the White House Domestic Policy Council. “This is not rocket science.”

The transparency order is part of the administration’s broader push to make health information more publicly accessible. Drug companies must state the price of their drugs in television advertisements now, and hospitals must already post on their websites the prices they charge uninsured customers.

The best available evidence about negotiated health care prices is that they range widely depending on the market, and on the hospital and insurer negotiating the deal. Hospitals tend to offer insurers bulk discounts for sending them customers. So a given insurer may get a low price for services at one hospital, but pay higher prices at its competitors.