Employers, insurers, media organizations and consumer groups interested in physician quality have been pressing the government to open up the files. Last week, the Obama administration announced it would do so.
Over time, public access to the data could change the way medicine is practiced in America. Combining the billing data with other sources of information, analysts would essentially be able to peer over the shoulders of individual physicians. Doctor ratings, now often based on the opinions of other physicians, would be driven by hard data, like statistics on baseball players. Consumers could become better educated about the doctors in their communities.
For example, if you're about to undergo heart bypass, you could find out how many operations your surgeon did last year. Research shows that for many procedures, patients are better off going to a surgeon who performs them frequently.
The data could also be used to spot fraud, such as doctors billing for seeing more patients in a day than their office could reasonably be expected to care for.
Medical practice would have to change to accommodate big data. Insurers, acting as the intermediaries for employers and government programs, could use the Medicare numbers to demand that low-performing doctors measure up. If the data indicated a particular doctor's diabetic patients were having unusually high rates of complications, that doctor might face questions.
Such scrutiny would probably accelerate trends toward large medical groups and doctors working as employees instead of in small practices.
"Over the past 30 years, the landscape has changed with respect to physician information that is available to the public," Medicare deputy administrator Jonathan Blum said in a letter last week to the AMA. "As a result, the health care system is changing from a system dominated by dearth of usable, actionable information to one where care coordination and dramatically enhanced data availability ... will power greater innovation, higher quality, increased productivity and lower costs."
The AMA responds that unfiltered files may contain inaccuracies. It worries that the numbers may not look good for accomplished doctors who take on the most severely ill patients, or for practitioners working in economically depressed areas. The group is asking the government to allow doctors to review and correct their information prior to its release.
A "broad approach to releasing physician payment data will mislead the public into making inappropriate and potentially harmful treatment decisions and will result in unwarranted bias against physicians that can destroy careers," said AMA president Ardis Dee Hoven.
The data has limitations. The administration is only releasing billings for 2012, so trend analysis won't be possible. Also, it doesn't include beneficiaries in Medicare Advantage plans offered through private insurers, more than 25 percent of seniors. And to protect patient privacy, data on doctors who treated 10 or fewer beneficiaries won't be released.
"This is a very good change in policy," said Robert Krughoff, president of Consumers' Checkbook, which rates insurance plans. "It is now up to consumer organizations to be sure the information is used in valid ways, and to be strongly critical of reports that use invalid methods that are misleading or unfair to physicians."
The AMA's decision does not rule out last-minute legal action by other groups.