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What the Polls Keep Missing in the Midterm Elections

There are multiple reasons why surveys have had a hard time capturing the success of this year’s crop of insurgent Democrats.

Supporters react last week after Ayanna Pressley won the Democratic primary in Boston. (Brian Snyder / Reuters)

The summer of 2018 has been full of progressive-insurgent wins—wins that have been pretty shocking for anyone relying exclusively on poll numbers to make predictions. No poll showed Boston City Councilor Ayanna Pressley ahead in her primary challenge to Representative Mike Capuano of Massachusetts until she won last Tuesday by 18 points. The Florida gubernatorial candidate Andrew Gillum was polling third or fourth out of five Democratic candidates before he defeated his opponents by a margin of three points. Internal polling showed Representative Joe Crowley with a 36-point lead over Alexandria Ocasio-Cortez, who ended up winning in New York’s Fourteenth District by 14 points.

As the last primary of 2018 approaches this week—Cynthia Nixon’s challenge to Governor Andrew Cuomo in New York—progressives wonder if they can again expect a come-from-behind victory. But it isn’t as simple as that: There are many reasons why the results of those earlier races were so different from the polls that preceded them, and those differences reflect some of the larger problems plaguing the polling business.

First off, pollsters point out, primary polling and general-election polling are two different beasts, and one is much messier. “Primary polling is excruciatingly difficult to do,” says Don Levy, the director of the Siena Research Institute, which conducts the Siena College poll. “If I wasn’t insane, I wouldn’t do it.”

There are technical difficulties associated with all kinds of surveys: The pollsters I spoke with cited increased cellphone use over landline phones—the device traditionally used in polling—and a decreasing number of people willing to answer a call from an unknown number as significant hurdles. But what complicates primary polling in particular is that voters don’t typically pay as close attention as they do in general elections. That’s especially true in primary elections in midterm years like this one. Compounding that problem, the choices in a primary aren’t as simple as Republican versus Democrat; there’s less of an ideological distinction between candidates, so the choice is more difficult for voters to make.

All of these factors means that polls conducted in advance of a primary election are imprecise, and can’t be used as reliable predictions. The pollsters I spoke with repeatedly stressed that polling is merely a snapshot in time, which means a poll taken in the weeks before a primary will often reflect voters’ indecision.

Surveys that showed Pressley 13 points behind in Massachusetts, for example, weren’t necessarily wrong—those who used them to predict a Pressley loss simply assigned them too much weight. “I think it was too old for it to really be used as predictive,” said Steve Koczela, the president of MassINC Polling, a research company that conducted a survey of the race for WBUR in Boston. “I went back and found that a lot of people didn’t know who Pressley was in July. There are a lot of things that changed in the month of August.”

Aubrey Jewett, a political-science professor at the University of Central Florida, said a similar thing likely happened with Gillum in Florida. “There was a very large number of respondents that were undecided in the last few weeks of the campaign,” he explained, “so, many voters hadn’t made a choice” at the time the polls were taken.

The most challenging issue facing pollsters in 2018 has been anticipating turnout in elections where candidates are specifically trying to attract infrequent or unlikely voters. Primary pollsters survey “likely voters” to get an accurate read of a primary, and they define “likely voters” by how often they’ve voted in previous primaries, how interested they say they are in a particular race, and a slew of other factors. It’s hard to get a representative sample of people to poll when you don’t know who’s voting. “What you’re trying to do is anticipate what someone is going to do at some future date,” said J. Ann Selzer, the president of an Iowa-based polling firm with an impressive record of predicting Iowa primary winners. “How do you take your best shot at predicting what someone will do?” It’s a problem primary pollsters always face—and one that, if progressives are successful in their attempts to expand the electorate, will only get worse.

“There is a bias to look backwards to predict the future … When there’s a reaction against the present that changes who’s going to turn out in the future, some of those models can miss,” Selzer said. “There may be people who haven’t traditionally voted before, but now their neighbor knocks on [their] door and says, ‘Let’s go!’”

Turnout is part of an integral question facing the Democrats: How should they position themselves ahead of the midterms and 2020? While the Democratic National Committee has focused on turning districts from “red to blue,” progressives say they’d rather focus on mobilizing new voters, especially young people and people of color. Because there aren’t usually exit polls conducted in state- and district-level primary elections, it’s hard to draw firm conclusions about who voted for this year’s insurgent candidates. But the pollsters I spoke with said all signs point to increased turnout and increased involvement by young and nonwhite voters.

In Florida, for example, primary turnout eclipsed numbers from the 2014 midterm elections, and it’s likely that pollsters just didn’t get an accurate sample of Gillum’s base, Jewett said. “Anecdotally, it seems like there was a big surge in black turnout,” Jewett said, explaining that the progressive African American candidate did “extraordinarily well” in urban areas and small counties with high black populations. “Younger voters anecdotally seem like they may have turned out at higher levels as well.”

In Massachusetts’s Seventh District, where Pressley ran, more than 100,000 voters came to the polls—twice as many people as those who showed up in the past three primary elections in the district. Preliminary results show that Pressley did especially well in precincts with young voters and people of color. Precinct-level data also suggests that, although turnout was low in New York’s Fourteenth District, Ocasio-Cortez defeated Crowley by turning out young progressives.

The polls taken ahead of the New York gubernatorial primary on Thursday aren’t promising for Nixon. The most recent survey, from Siena College, showed her trailing Cuomo by 41 points. But Nixon’s supporters are still optimistic that she’ll be the next insurgent candidate to overcome ominous polling data. After all, they’re just a snapshot.