Both parties should find much to like in such an approach. It would offer Republicans a way to constrain the growth of government spending and take pressure off private businesses weighed down with health expenses. And it would offer Democrats a means of preserving the integrity of Medicare and Medicaid and thereby restoring faith in a core government function.

And yet getting funding for the research needed to assess and compare medical treatments has been like pulling teeth. As a rule, legislators seem to lack a natural affinity for economists and budget analysts (alas, they are hardly alone). But Peter made himself exceptionally unpopular with some Democrats and many Republicans by insisting on such funding in the 2009 stimulus bill, and then working to expand it in the 2010 “Obamacare” legislation. Despite these modest successes, less than $1 out of every $1,000 that the government spends on health care this year will go toward evaluating whether the other $999-plus actually works.

Getting the right information is less than half the battle. Acting on it, once it’s in hand, is harder still. As one small example, some evidence suggests that moving toward “bundled” payments for all services needed by a patient during a course of medical treatment could produce better value than paying piecemeal for each service and procedure, because the piecemeal approach creates an incentive for more care rather than better care. During one meeting with members of Congress in 2008 to discuss how to expand bundling and include a performance incentive in kidney dialysis, Shelley Berkley, a Democratic congresswoman from Nevada, accused Peter, as he remembers it, of trying to destroy the dialysis industry. “You and your staff may have your Ph.D.s, but you have no clue,” he recalls her saying. “We don’t need any of your fancy analysis.” (Berkley says she does not remember the meeting, or those comments.) Berkley had received campaign contributions from several dialysis companies and organizations, and her husband owned a dialysis business. Whether these factors may have influenced her thinking is a question we will leave for the reader.

It is indisputable, however, that a move toward payments based on performance would harm some business interests. If most of your profits come from, say, a medical device or procedure that is covered by Medicare but doesn’t work all that well, you’re likely to resist anyone sorting through what works and what doesn’t, never mind changing payment accordingly. Health-care interests are wise to invest millions of dollars in campaign contributions and lobbying to protect billions of dollars in profits.

Your other author (John) received his own lessons on why moneyball doesn’t play in Washington a few years earlier, when he joined the administration of George W. Bush. Bush, of course, was not only a former baseball-team owner but also the first president to hold an M.B.A. In every domestic-policy briefing John led in the first term of the Bush administration, the president would ask some version of the following questions: How do we know this program will achieve the results as advertised? Who will run this program, and is that person an effective manager? How will that person and the program be held accountable for producing results?