One theory about why Donald Trump did better on election day than pre-election polls had suggested is that some people were too “shy” (embarrassed?) to admit to a pollster that they were going to vote for Trump. Harry Enten of Fivethirtyeight.com says that the evidence just doesn’t support that this really happened.
The bottom line is that Trump did better than the polls predicted, but he didn’t do so in a pattern consistent with a “shy Trump” effect. It’s more likely that polls underestimated Trump for more conventional reasons, such as underestimating the size of the Republican base or failing to capture how that base coalesced at the end of the campaign.
And more to the point:
…Trump didn’t outperform his polls with the specific group of voters who research showed were most likely to hide their support for his candidacy. A Morning Consult study conducted in October found that there were some “shy” Trump voters, enough to suppress his support in polls by a statistically insignificant 2 percentage points. But the study found that the voters most likely to lie to pollsters were those with college degrees. So under the “shy Trump” theory, we’d expect to see Trump outperform his polls on Election Day in states such as Massachusetts and New York with high numbers of people with college degrees. But instead, Trump did better than his polls in states with the highest concentration of white voters without a college degree, including pivotal states such as Michigan, Pennsylvania and Wisconsin.