Regardless of what happens between now and the GOP convention, there is little doubt that Donald Trump has undermined our understanding of primary politics. It will probably be years before political scientists fully understand the Trump phenomenon, but much of his appeal seems to stem from the image he has cultivated that he is “not a politician.” Voters, the claim goes, can’t trust politicians, particularly to keep their promises. But they can trust Trump. The problem with this claim? It gets reality almost exactly backward.

In framing the choice this way, the Trump campaign is tapping into a widespread belief Americans have about politicians: They lie. A Rasmussen survey in 2014 found that just 4 percent of likely voters that year believed that “most politicians” kept the promises they made on the campaign trail, while 83 percent did not. (The remaining 13 percent were undecided.) Similarly, when The New York Times asked respondents in 2009 if President Obama would be able to keep his promise not to raise taxes on Americans making less than $250,000 a year, 56 percent said no. More broadly, the General Social Survey in 2012 asked people whether they agreed that candidates elected to Congress try to keep the promises they made during the election — a majority (59 percent) disagreed.

It turns out, however, that in this case, the majority is wrong.

Political scientists have been studying the question of campaign promises for almost 50 years, and the results are remarkably consistent. Most of the literature suggests that presidents make at least a “good faith” effort to keep an average of about two-thirds of their campaign promises; the exact numbers differ from study to study, depending on how the authors define what counts as a campaign promise and what it means to keep it.

YEAR OF PUBLICATION TIME PERIOD STUDIED SHARE OF PROMISES KEPT 1968 1944-66 72% 1969 1932-64 80 1971 1944-66 72 1980 1944-78 69 1984 1912-76 71 1985 1960-80 61 1987 1945-79 64 1996 1980-88 52 1997 1977-92 60 1999 1976-92 60 2004 1997-99 73 Average 67 The history of U.S. presidents keeping their promises Source: Adapted from Pétry and Collette, “Measuring How Political Parties Keep Their Promises“

George W. Bush promised tax cuts and education reform, and within the first year of his administration had delivered on both. Barack Obama promised to focus on the economy, health care and the environment. Once in office, he pushed first a massive stimulus package and then the Affordable Care Act through Congress, and he has worked with China and others in the international community on climate change, despite strong legislative opposition. As for the promises that get abandoned, many have more to do with changing circumstances than a lack of principles. (Think of Bush, an ardent free-marketeer, signing the Troubled Asset Relief Program bill during the first tremors of the Great Recession.)

In recent years, the fact-checking website PolitiFact has been paying close attention to this question, and its numbers are largely in line with what scholars find. Examining more than 500 promises President Obama made during his two presidential campaigns, PolitiFact finds that he has fully kept or reached some compromise on 70 percent of them. Similarly, Republican leaders made, by PolitiFact’s count, 53 promises before taking over Congress in 2010; 68 percent of these have been partially or fully kept.

This pattern isn’t unique to America. Scholars in Canada and Europe have examined the phenomenon and found their politicians to be, if anything, even more trustworthy. (The gap probably reflects added incentive — and increased opportunity — politicians have to carry out their policies in a parliamentary system where one party controls both the legislative and executive branches of government.) Across both time and borders, then, the data in this case is fairly clear.

COUNTRY NUMBER OF STUDIES SHARE OF PROMISES KEPT Great Britain 2 82.5% Canada 2 73.0 Greece 1 70.0 United States 11 66.7 Netherlands 1 61.0 Weighted average 17 69.2 Political promises kept by country Source: Adapted from Pétry and Collette, “Measuring How Political Parties Keep Their Promises“

On the one hand, it makes perfect sense that politicians would work to keep their promises — after all, re-election is a powerful motivator, and if you hired a contractor to remodel your kitchen and she had the construction crew put a Keurig machine where she told you the dishwasher was going to go, you probably wouldn’t hire her again when it was time to redo the master bath. On the other hand, though, it’s easy to understand why voters feel ignored. “Read my lips: no new taxes” and “if you like your health care plan, you can keep it” are dramatic moments that both command greater media attention and loom larger in our minds than the hundred quieter ways in which presidents (and other politicians) work to do what they said they were going to do.

But there is perhaps a double irony to Trump benefiting from this misperception. He, unlike many of those he criticizes, really doesn’t seem to be interested in keeping his promises. Obviously, we can’t (yet) compare his rhetoric to his performance in office, but we can examine how well his rhetoric lines up with the plans his campaign has released and with his own past actions. And the mismatch is striking.

When he released his tax proposal, for instance, he claimed that it would raise taxes on the super-rich (“it’s going to cost me a fortune”), a claim he reasserted this month in an interview with the Washington Post. But more than one independent assessment has found the opposite — by one estimate, the after-tax earnings of the top 0.1 percent would increase by an average of $1.3 million. Similarly, he has suggested that the government has an obligation to guarantee universal access to health care coverage, but his health care plan returns to insurance companies the right to refuse sick applicants, a power denied to them since Obamacare became the law of the land. Even on his signature issue of immigration, Trump’s own past, in which his company used undocumented workers on a building project, is at odds with his current position. (Trump claims not to have known the workers were undocumented, but the judge in the case held his company responsible.) And that’s not to mention the hundreds of times Trump or his businesses have been sued for not meeting their contractual obligations.

In fairness, Trump too would probably attempt to keep his biggest promises were he elected in November. His plans to build a wall on the Mexican border, for instance, have probably been too specific and repeated too often for him to walk away from them, either as part of a general election strategy or in office. But on many other issues, it is difficult even to say what promises observers should score him on, as his rhetoric on the stump doesn’t match the official plan published by his campaign. Trump, then, is right to say he is not a typical politician: The best evidence we have suggests that the bulk of his promises really are as unreliable as voters wrongly assume his peers’ to be.