Don’t breathe a sigh of relief just yet—polls have been consistently wrong

How trustworthy are the polls, really?
How trustworthy are the polls, really?
Image: Reuters/Mike Segar
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Based on persistently terrible polls, Republicans are sweating a nightmare scenario in which not only does Donald Trump get steamrolled by Hillary Clinton, but his foul mouth sinks the Senate and House too, sending them into Democratic hands.

But pollsters have been misfiring around the world for more than two years now: They incorrectly forecast the 2014 US midterm elections, plus elections in Turkey, Scotland, Canada, and Israel. They also got Brexit wrong, and Greece, too—not once, but twice.

So can we trust them this time?

Poll aggregators currently give Clinton a 5.3% lead over Trump and the two other independent candidates. In fact, apart from a couple of blips, they have had her ahead of Trump for the entire presidential race. One outlier is the USC Dornsife/LA Times Poll, which has consistently favored Trump or has declared the race a tie. Another is Rasmussen, which currently has Trump ahead by 2%.

Studying these polls, Trump has been arguing that the election is fixed and is naturally latching on to the polls that favor him. His apparent objective is to infuriate his followers and create a post-election distorted reality in which the vote was stolen on behalf of Clinton. At the Washington Post, Chris Cillizza argues that, for professional reasons, Trump is likely to keep arguing this claim for the rest of his life.

Alan Abramowitz, a polling expert at Emory University, thinks the mainstream polls have it right this time. ”The better polls—the live interviewer polls that call cell phones and the higher-quality online polls, excluding crap polls like Rasmussen and LA Times/Dorsnlife—show Clinton with a solid lead,” Abramowitz told Quartz. “It’s not really close. She’s ahead by 6 to 7 points nationally, and she’s ahead in almost every swing state by similar margins.”

David Paleologos, who directs a poll carried out at Suffolk University in Boston, said there is some uncertainty in the polls partly because of an unusually large percentage of undecided voters, not to mention that Clinton and Trump are not the only candidates—Libertarian Gary Johnson and the Green Party’s Jill Stein also account for votes in the single digits. “The presence of both of these factions makes the race a little more fluid than in past presidential elections because we are looking at 15% of likely voters instead of [the usual] 7%” who are undecided, he told Quartz.

Trump has kept up a drumbeat that he will defy the polls in the same way that the Brexit outcome—in which UK voters last June elected to leave the European Union in a surprise upset—confounded the experts. In fact, he seizes on Brexit almost as proof that he will win.

But Abramowitz says this is wrong on a couple of counts. “The Brexit polling was close and, in fact, polls showed Brexit leading until shortly before the end, when the anti-Brexit side pulled slightly ahead. And that was a referendum, where voter preferences are less stable,” he says. ”In the US election, preferences tend to be highly stable, and there are few truly undecided or persuadable voters.”