The federal government is running most of the state health care exchanges, but the political battle over Obamacare is increasingly playing out in the states, whose governments must decide how to implement the law and whether to allow residents expanded coverage under Medicaid. Politicians across the spectrum spun a range of narratives about last week’s launch of the exchanges, which saw high traffic and embarrassing technical glitches. These are only the first steps in a long rollout process that is sure to be politicized even further.

Unfortunately, the public continues to be confused and ill-informed about the health reform law. In particular, a number of misperceptions about the ACA linger, including the false claim that it would create “death panels.” As insurance plans offered through the exchanges take effect next year, even more myths and falsehoods about Obamacare are likely to emerge as elected officials make bogus claims about the risks or benefits to the public.

( PHOTOS: 25 unforgettable Obamacare quotes)

Research shows that it is difficult to correct misperceptions when people are motivated to believe in them. However, we can still improve the debate over Obamacare by reducing the incentives for elected officials to make false or misleading statements about the law. Ideological stalwarts might not change their beliefs about the proper role of government in health care, but they are capable of changing the claims they make publicly about the law and its implementation. The question is how to get them to do so.

Our research suggests that politicians are generally sensitive to the possibility that statements they make will be publicly fact-checked. Currently, the claims politicians make about Obamacare receive too little scrutiny from the media, especially at the state and local levels. Even if a dubious statement is covered in the press or recorded and disseminated online, news outlets ranging from ABC to The Associated Press have proved susceptible to reporting such events in a neutral “he said, she said” manner rather than attempting to set the record straight. As a result, political figures have little reason not to make misleading assertions.

More aggressive fact-checking could help change those incentives. During the final months of the 2012 election, we conducted a field experiment among nearly 1,200 legislators from nine states in which affiliates of the nonpartisan fact-checking website PolitiFact were in operation. Starting in August 2012, we sent letters to approximately 400 of those lawmakers describing how negative fact-checking ratings could threaten their reputations and electoral prospects.

( WATCH: Kentucky residents react to Obamacare roll-out)

In our study, 2.7 percent of legislators who were not sent reminders about fact checking received a negative PolitiFact rating or had the accuracy of their statements questioned publicly. Among legislators who were sent warning letters about fact checking, this likelihood declined to just 1 percent — a 63 percent decrease in relative risk. These results, which we describe further in a New America Foundation report and academic working paper, suggest that fact checking can help to change politicians’ behavior, which in turn could have major implications for how well the public understands important policy issues.

The problem is not only the lack of fact checking in the media but also the targets that fact checkers select. Most of their efforts during the 2012 election were devoted to the presidential campaigns, which are relatively insensitive to negative coverage and wield vast advertising budgets that allow them to overshadow the press. State officials typically receive far less coverage, including very few fact checks. As a result, we should expect them to be more sensitive to the added scrutiny of fact checking.

Politics is inevitably messy. But fact checking can improve the odds that at least one of the news options in the health care debate contains the truth.

Brendan Nyhan is assistant professor of government at Dartmouth College and a media critic for Columbia Journalism Review. Jason Reifler is senior lecturer in politics at the University of Exeter.