Eric M. Patashnik, Alan S. Gerber and Conor M. Dowling’s new book, “Unhealthy Politics: The Battle over Evidence-Based Medicine,” provides some very important insights into the role that evidence does (and doesn’t play) in U.S. policymaking. I asked Patashnik, a professor of public policy and political science at Brown University, about the book’s major findings.

Your research suggests that the U.S. health-care system has massive inefficiencies, and that many patients receive treatments that don’t help them and sometimes cause harm. Although health care is much more expensive than it is in other countries, a majority of U.S. doctors say that the quality is the same as or even worse than in Western Europe. How did we end up here?

Many Americans assume that treatments are based on sound evidence, and that when they are found not to work, they will be quickly abandoned. In reality, treatments can diffuse into clinical practice before they are evaluated. Once doctors begin using a treatment, it can become hard to stop, even if studies show it works less well than alternatives.

The political constituency for evidence-based medicine is weak. The public worries that payers will use medical evidence to ration care, or to limit doctors’ ability to tailor their care. Our survey research shows that the support of doctors for the use of evidence to guide medical care can allay the public’s fears. However, doctors have not consistently led on this issue. Many doctors support evidence-based medicine in the abstract, but bristle when studies question the effectiveness of treatments in their practice areas.  And politicians recognize that picking a fight with doctors is not a winning reelection strategy, despite mounting concerns about the efficiency and quality of health care.

What kinds of specific evidence do we have about waste?

A large body of research shows that the uptake of medical evidence is often slow and haphazard. For example, we looked at the use of arthroscopic surgery to treat osteoarthritis of the knee. In 2002, the New England Journal of Medicine published a study that demonstrated that the surgery worked no better than a sham procedure in which a surgeon merely pretended to operate. We wondered how the health-care system would respond to this study, and why this operation had diffused into practice in the first place.

We found that surgeons became excited about the procedure and began performing it on their patients before there was hard evidence about its effectiveness. When the sham surgery study came out, medical societies challenged it on questionable grounds and lobbied to maintain Medicare coverage of the procedure. The use of the operation eventually declined, but surgeons continue to perform closely related procedures that also rest on a weak evidence base.

Why are doctors so resistant as a profession to evidence-based medicine, and are there differences in how Democratic and Republican doctors think about evidence?

We performed a national survey of physicians to learn how doctors see their own role in causing and combatting waste and inefficiency in health care. We found that many doctors are poorly informed about these issues. For example, only one-fifth of the doctors in our survey said they were “very” or “somewhat” familiar with research on geographic variation in health care spending and utilization, despite the vast attention this research has received from experts concerned about the delivery of low-value care.

Not only are most doctors not up to speed on this body of knowledge, but they are comfortable with medical societies advocating for their professional autonomy and economic interests when treatments are challenged by research. We asked doctors what they want their medical societies to do when a study calls into question the effectiveness of a treatment commonly used in their practice area. The most preferred response by doctors (almost 75 percent) was for medical societies to take an active role in critiquing the quality of the study and point out any weaknesses. In contrast, just 52 percent of doctors supported the medical society playing a neutral information transmission role without taking a stance. In sum, many doctors want medical societies to act like trade associations — but the public doesn’t necessarily recognize this.

Although doctors overall want medical societies to defend clinical autonomy, we also found some differences among the views of doctors based on their partisan affiliation. Doctors who identify as Republicans rated finding ways to cut health-care costs by discouraging clinical interventions with minor or no benefits as somewhat less important priorities for societies than did doctors who identify as Democrats. Republican doctors also appear somewhat less comfortable than Democratic doctors with evaluating physicians in terms of their adherence to simple metrics, such as the faction of their patients who receive flu shots of whether cardiac patients are taking appropriate medications.

Have there been reforms to promote evidence-based medicine, and if so have they worked?

Some reforms have been adopted but they have had only limited success. In 1989, the Agency for Health Care Policy and Research was created to develop practice guidelines and improve the efficiency and quality of care. It set off a firestorm when it released a report supporting nonsurgical treatment for low-back pain. Back surgeons argued that the government has no business telling doctors how to practice medicine. In response, Congress slashed the agency’s budget and narrowed its authority.

More recently, the Affordable Care Act established the Patient-Centered Outcomes Research Institute (PCORI), an independent, nonprofit organization that funds studies to compare health-care options to learn which works best. This a valuable step, but PCORI has not yet had a major impact on clinical practice.  It has a narrow research mission, and (by design) doesn’t make policy recommendations.  The agency has not yet gained a reputation for relevance among the general public. PCORI’s authorization expires in 2019, and it is unclear if it will survive.

Given the huge amounts of money to be saved by curbing waste, why have politicians been so reluctant to embrace the cause of evidence-based medicine?

The American political system is often claimed to have properties of self-correction. When governance veers off course, opportunities may arise for “political entrepreneurs” to frame problems and “sell” solutions to the public—to capture a political reward.

But the medical evidence problem has prompted only limited investments of political entrepreneurship from officeholders. It is risky for politicians to challenge the medical authority of doctors, even when scientific evidence is on the politicians’ side. The public trusts doctors much more than they do politicians, and politicians fear they will take a reputational hit if they question whether doctors always know best. We call this “zero-credit” politics: a policy problem can persist because politicians are unable to claim credit from working to solve it.

A second breakdown occurs at the decision making stage, and is driven by polarization and partisan competition. One might have expected conservatives to have supported PCORI since they had long expressed concerns about wasteful medical spending. But the battle over Obamacare undermined the incentives for a bipartisan, technocratic consensus on the need for taxpayer support for evidence-based medicine research. (One Republican congressional staff member told us that GOP support for PCORI was a casualty of the partisan “knife fight” over the ACA; in the middle of a knife fight, he said, you don’t pause to tell your opponent you like his shirt).

If the supply of pragmatic problem-solving is too low even in a sector as important and salient as health, it is likely to be inadequate in other sectors as well.

This article is one in a series supported by the MacArthur Foundation Research Network on Opening Governance that seeks to work collaboratively to increase our understanding of how to design more effective and legitimate democratic institutions using new technologies and new methods. Neither the MacArthur Foundation nor the Network is responsible for the article’s specific content. Other posts in the series can be found here.