Yes, I know we don’t like “study sez” stories; that is unless they trumpet a new cancer drug or a cure for obesity. But sometimes a study comes along that merits a second look.

That was the case with a report from the RAND Corporation last week, which challenged a lot of the conventional wisdom about emergency rooms—that people, especially the uninsured, use them like a family doctor’s office, run up big bills that are bankrupting the US health system, and must be penalized by insurers if they use them when they shouldn’t.

Instead, the study found that it is not patients but doctors—yes, doctors—who are increasingly responsible for increases in volume in the nation’s emergency rooms. Secondly, the study argued that ERs have a significant role to play in the healthcare system and may in fact help prevent some unnecessary hospital admissions, a major driver of spending. In fact, in the war on ever higher healthcare spending, the study seemed to push back on the notion that emergency rooms are a major villain.

The trade press picked up the story—sort of—presenting bits and pieces of it in short takes. The mainstream media did not. Among the exceptions: Reed Abelson of The New York Times, who got it right, reporting that RAND’s findings raise important questions about the future of healthcare.

“It’s a ‘fact-resistant idea’ that emergency departments are inappropriate sites of care,” says Dr. Arthur Kellermann, an ER doctor and senior RAND researcher who also was one of the study authors.

And Kellermann gave me some fairly startling figures: that emergency department care accounts for between 3 and 6 percent of total healthcare spending—versus about 31 percent for inpatient care. “The average cost of an ED visit is $900,” Kellermann pointed out. “It’s 10 times that for the average hospital stay.”

Kellermann and his colleagues found, through data analysis and interviews with ER and primary care physicians, that doctors are sending patients to emergency rooms in higher numbers in response to their tightly packed schedules—the fact that they have less and less time to examine more and more patients. “The doctors said, ‘the ER is my overflow valve. It’s where I send complicated patients. It’s become my diagnostic center,’” Kellermann told me. “An increasing percent of acute care visits are going to emergency departments as opposed to seeing personal physicians.”

Kellermann did not say so, but hospitals, too, might be boosting the numbers of ER visits through marketing campaigns aimed at getting more people to use the ERs, in their quest for higher revenue. Emergency rooms are indeed the most expensive places to provide care.

Yet more people entering the system through the ER may not be a bad thing, RAND researchers concluded, suggesting they could even gain in importance in the redesign of American medicine that is occurring because of both market forces and Obamacare. The researchers found that most people who go to ERs do so because they have no other source of care—not because it was convenient, as conventional wisdom has it.

The study was funded by the Emergency Medical Action Fund, a consortium of ER physician groups, which wanted to know more about how emergency rooms shape US healthcare.

Emergency Rooms have become a gateway for hospital admissions; the researchers found that they account for about half of all inpatient admissions. But at the same time, they also believe that ERs may help limit preventable hospital admissions, which, of course, could save the system money.

Trudy Lieberman is a fellow at the Center for Advancing Health and a longtime contributing editor to the Columbia Journalism Review. She is the lead writer for The Second Opinion, CJR’s healthcare desk, which is part of our United States Project on the coverage of politics and policy. Follow her on Twitter @Trudy_Lieberman.