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Here’s a key theory behind cutting health care costs: If consumers knew how much they’d have to pay for various medical services, they could be savvier shoppers, which would ratchet up competition among doctors and hospitals, to cut prices. 
So, employers and insurers created online tools to help folks distinguish costly providers from less expensive alternatives.
But a new study out today, published in the Journal of the American Medical Association (JAMA), raises some doubts about whether these tools are working.
Say you live in a place where an MRI costs anywhere from $400 to $4,000. In response, companies hire firms like Castlight and IBM’s Truven Health Analytics to give that price information to their employees.
Harvard Medical School’s Michael Chernew, who studies health care policy, worked with a team of researchers to look at two large employers who fired up Truven’s online pricing tool.