Is there a pool of voters who are too embarrassed to admit to pollsters they’re voting for Donald Trump?

As Trump consistently lags Hillary Clinton in general-election polls, his campaign is counting on it.


The notion of the “shy Trump voter” refers to the theory that there’s a group of voters who won’t admit their support for Trump in phone surveys, but will actually choose the controversial, presumptive GOP presidential nominee this fall.

Earlier this month, the New York real estate mogul said at an event that he does “much better” in elections than in pre-election surveys, making a passing reference to the phenomenon known as the Bradley Effect — coined after the African-American mayor of Los Angeles who led in polls but lost unexpectedly in the 1982 California gubernatorial race. The idea that Trump might be under-polling was echoed again last week, after the United Kingdom voted narrowly to leave the European Union, despite polls showing the referendum to be a tossup — a campaign that centered on many of the same issues that Trump is touting in the U.S. presidential race.

But there’s little evidence that shy Trump voters actually exist. In the Republican primaries, he didn’t outperform his poll numbers relative to his leading challengers — and, until he ran away with the nomination in late April and May, he performed significantly worse than the polls suggested.

While the general election is more than four months away, the best real-world test of this theory also shows no indication Trump is poised to outrun his poll numbers: Trump’s average deficit against Clinton is actually smaller in surveys conducted by a live telephone interviewer than in automated or online polls without a live person on the line.

Overall, Clinton leads Trump by nearly 7 points, according to averages calculated by HuffPost Pollster and RealClearPolitics. That represents Clinton’s largest lead since before Trump knocked out the last contenders for the GOP nomination and surged into a tie with Clinton.

Trump has said, on occasion, that the polls aren’t true measures of the race. He called this week’s ABC News/Washington Post poll “dirty” because Democrats outnumbered Republicans by 10 points among registered voters. (Most public pollsters don’t weight their survey data according to party identification.)

And on other occasions, Trump has suggested that the polls can’t accurately measure his support. Alluding earlier this month to Tom Bradley’s experience in California — though he declined to use Bradley’s name — Trump said the phenomenon that led some voters to tell pollsters they were going to vote for Bradley but to choose the white candidate, George Deukmejian, instead was occurring this year, too.

“He was supposed to win by 10 points, and he lost by 5 or something. So it’s a certain effect,” Trump said, referring to Bradley. “Now, I have — unfortunately, maybe fortunately — the opposite effect. When I poll, I do fine. But when I run, I do much better.”

“In other words, people say, ‘I’m not going to say who I’m voting for,’” Trump added. “And then they get it, and I do much better. It’s like an amazing effect.”

Pollsters call this social-desirability bias. Voters misrepresent their intentions to provide responses that might be viewed more favorably. Or they could decline to be interviewed entirely to avoid giving responses they view as socially undesirable.

This phenomenon is seen in surveys on other topics. Respondents understate some negative health behaviors, for example. Far more people tell pollsters they intend to vote than will end up casting ballots. And, after an election, a larger percentage of voters say they did participate than vote totals indicate.

Bradley’s 1982 defeat is the most widely recognized example of social-desirability bias swaying an election. There were concerns in 2008 that Barack Obama could underachieve compared to his poll numbers, but those proved unfounded.

More recently, referenda on same-sex marriage — including California’s Proposition 8 in 2008 and similar initiatives in other states — may represent examples of social-desirability bias: Voters may not want to say they will vote to ban same-sex marriage but tell pollsters they would vote against those measures. Proposition 8 passed in California in 2008 by roughly the same margin polls indicated. But a gay-marriage ban passed by a larger-than-expected margin in North Carolina in 2012. Later that same year, Maine voters elected to legalize same-sex marriage in the state, though by a much smaller margin than polls suggested.

There are two tests of whether a similar circumstance is developing with regard to Trump. First, the elections that have already taken place: On balance, Trump’s performance in the Republican primaries didn’t exceed his poll numbers to any significant degree. In the 22 states where there were enough public surveys for RealClearPolitics to calculate a polling average, Trump earned, on average, 2.4 points more in the primaries and caucuses than the polling average.

But that difference doesn’t mean Trump outperformed his polling. First, polls include undecided voters, who end up choosing a candidate or staying home on Election Day. And Texas Sen. Ted Cruz, the only other candidate to earn more than a quarter of the overall vote, outperformed his poll numbers by 2.5 points on average.

Trump’s strength, relative to his pre-election poll numbers, is also biased by his late break-away from the Republican field. In the first 17 contests for which there were polling averages, running through the April 5 Wisconsin primary, Trump outperformed his polls by an average of 0.9 points. Cruz, on the other hand, earned about 3.7 points more in these primaries and caucuses than the polls suggested. In other words, Trump badly underperformed his rivals — relative to their pre-election poll numbers — until GOP primary voters moved his way in the Northeast and Mid-Atlantic states, and he locked up the nomination.

The Cruz campaign, which built the most comprehensive data and polling operation of all the GOP candidates, didn’t see any sign of below-the-radar Trump voters.

“We saw zero evidence in the primary of a ‘shy Trump’ effect,” Cruz pollster Chris Wilson said in an email. “Not only did Trump not outperform his poll numbers in our data, he often underperformed where he was in the public polling (Iowa and Wisconsin being well-reported examples). Bottom line is, we had no challenge accurately measuring Trump voter support — for better or worse.”

Just because the phenomenon didn’t occur in the primaries doesn’t mean it won’t in the general election. But the different ways in which pollsters conduct their surveys can replicate the secret ballot to some degree.

Former House Speaker Newt Gingrich, who has emerged as a Trump surrogate, made this suggestion Tuesday.



"What happens is the elites, the establishment all pile on. The average citizen will not tell pollsters the truth,” Gingrich said Tuesday morning on Fox News Channel. “You get much better results for Trump for example in a computerized online poll than a telephone poll because people don't want to tell the pollster something they think is not socially acceptable.”

But that’s not what the current data indicate. Clinton’s lead over Trump in telephone polls conducted by live interviewers stands at 5.3 percentage points, according to HuffPost Pollster. By contrast, Clinton leads by 5.9 points in polls conducted online or by automated phone messages, when there isn’t a person on the other end of the line.

If the "shy Trump voter" theory were accurate, one would expect Trump to run stronger in the online and automated phone polls, which more precisely simulate the anonymity of the voting booth. But he is actually weaker in these surveys, at 39.2 percent compared to 40.1 percent in live-phone polls.

