Pollsters in Iowa are searching for answers after they failed to predict Ted Cruz’s victory over Donald Trump and Marco Rubio. It might even be worse next week in New Hampshire.

Pollsters and other observers surveyed by POLITICO this week pointed to a number of reasons why New Hampshire is such a uniquely difficult state to poll. Chief among them: The volatility in the electorate that persists right up until voting begins.


“People are moving around from candidate to candidate,” said Dante Scala, an assistant professor at the University of New Hampshire and author of a book on the state’s first-in-the-nation primary. “I think if you called the same person in two successive nights, you might get two different answers of who they like.”

Recent polls indicate that Rubio, the first-term Florida senator who placed third in Iowa, is the early beneficiary of the post-caucuses momentum. Early tracking polls – a daily tracker launched this week by the University of Massachusetts-Lowell, and a small-sample, post-Iowa survey from the University of New Hampshire – show Rubio’s numbers ticking up.

While the changes aren’t huge at the moment, they are significant in this regard: Rubio is seeking to parlay his momentum to break away from a pack of candidates who had been jockeying for second place behind Trump, a group that includes Cruz, Jeb Bush, John Kasich and Chris Christie. (The early post-Iowa surveys show Cruz slightly ahead of Bush and Kasich, with Christie sagging lower.)

But before Rubio starts writing his victory speech Monday night, it’s worth recalling the most famous example of the failure of pre-election surveys to predict the outcome of the New Hampshire primary.

On Jan. 3, 2008 – the day of the Iowa caucuses – Hillary Clinton led Barack Obama by 7 points in the RealClearPolitics average of New Hampshire polls. And then Obama won Iowa.

Despite just four days separating Iowa and New Hampshire, Obama quickly surged in the polls, opening up an 8.3-point lead in the final RCP average.

But something happened on the way to an Obama sweep of the first two states: Clinton stormed from behind in the race’s final 24 hours, leading pollsters – including the industry’s professional organization, the American Association for Public Opinion Research – to conduct thorough reviews of industry practices.

Their most basic conclusion: Polls that stop days before the primary miss important shifts in voter preference that occur right up until Election Day.

“Late deciders haunt everybody,” Scala said this week, recalling his expectation in 2008 that Obama would run away with the primary. “I remember watching the actual returns come in and realizing half an hour in that wasn’t going to happen.”

It’s a lesson the pollsters who survey New Hampshire are taking to heart. Late-deciding voters are the biggest reason why pollsters are lowering expectations that the pre-primary surveys will match the results next Tuesday.

“We expect way too much of polls, more than they could possibly deliver,” said University of New Hampshire pollster Andy Smith, who is conducting surveys for CNN and Manchester's WMUR-TV. “We’re asking people what they plan to do, and they really don’t know.”

“These people really are volatile,” added Monmouth University pollster Patrick Murray. “They really are undecided. Even if they pick a candidate today or tomorrow, they can change their mind.”

The seven-day interval between the Iowa caucuses and the New Hampshire primary last year, while longer than 2008, also poses challenges.

“It comes very soon after Iowa, which is a major news event,” warned Steve Koczela, the president of the MassINC Polling Group, which polls the state for WBUR-FM, the Boston-area NPR affiliate. “Any time you do a poll right after a major news event, you can expect changes. And the New Hampshire primary comes right during those changes.”

That leaves those polling New Hampshire with a limited window. They want to measure changes since Iowa, but the news organizations that commission those polls don’t necessarily want to wait until the last minute. (Besides, some pollsters believe releasing horse-race polls on Election Day is an unethical practice that could unfairly influence results.)

MassINC’s Koczela said the horse-race is only one reason why news organizations commission polls. A more important purpose, he said, is to provide a meaningful narrative of the campaign – even if that means leaving the field earlier and undermining the survey’s chances of more closely matching the election results.

“In terms of accuracy, it would be nice to poll right up until the very last minute,” said Koczela. “But there are other things that are important other than accuracy.”

That’s an issue in all elections – and late-deciders are a more acute problem in primaries, where voters generally like most of the candidates and aren't making their decisions based on partisan cues, as in general elections.

The timing of these surveys also highlights a common complaint among pollsters: Too much attention is paid to the horse-race, and their surveys are mostly being used to predict the results of elections.

“The public wants to know what the score is,” UNH’s Smith said, “but I think it behooves public opinion researchers that we try to tell the public the real story of what’s going on.”

Late deciders aren’t the only challenge facing New Hampshire pollsters. Some cited the state’s open primary system, in which unaffiliated voters can participate in either party’s primary.

Koczela pointed to the past two presidential races without an incumbent as evidence of how undeclared voters can shift. In 2000, he said, many of them participated in the Republican race to back Arizona Sen. John McCain over George W. Bush. But, in 2008, the Democratic race was more compelling, and independents were more likely to pull ballots in the Obama-Clinton contest.

“It means the electorate is quite different each time,” said Koczela. “There’s not a repeat of how things looked in a previous elections.”

Smith, however, insists Koczela and others are making too much of the independent factor. “Most of them are partisans,” he said. “They vote consistently partisan – and vote consistently in their party’s primary.”

Another complication: The sheer number of polls and calls from campaigns in the state has left voters dreading the ringing of their telephones.

“People in New Hampshire are inundated with calls and information and requests on their time,” said UMass-Lowell pollster Joshua Dyck. “It’s not only pollsters calling voters, it’s also campaigns calling voters.”

Yet there are also ways in which polling New Hampshire is an easier endeavor than Iowa. Pollsters cited the extremely high turnout rates for presidential primaries in New Hampshire, which can draw more than half the eligible voters. (In Iowa, on the other hand, fewer than one-in-five active voters participated in Monday’s caucuses.)

Pollsters said that makes it easier to ensure that they aren’t including too many non-voters in their surveys.

“Turnout here is so high,” said Smith. “Turnout in 2008, for example, was 54 percent [of voting-age residents]. No other state has anything like that.”

Pollsters are hoping they can avoid another in a long line of embarrassing misses in New Hampshire: Ronald Reagan won a landslide victory over George H.W. Bush in 1980, but the polls overstated the former California governor’s advantage. Walter Mondale led Gary Hart in the polls in 1984 after romping in Iowa, but Hart pulled the upset in New Hampshire.

In 1988, Gallup showed Kansas Sen. Bob Dole entering the New Hampshire primary with an 8-point lead over Bush.

“Dole was up by 7-to-10 points,” Marist College pollster Lee Miringoff recalled this week. “Everybody was saying, ‘Dole on a roll.’”

But Bush won by 9 points – leaving pollsters again to conclude that they should have kept polling to the end. Gallup left the field at 4 p.m. on the Sunday before the Tuesday primary.

''I was dismayed about the fact that we didn't put enough emphasis on the potential for things to turn around literally overnight,'' the late Andrew Kohut, then the president of The Gallup Organization, told The New York Times after the primary.

There’s no guarantee that there will be a similar, last-minute shift in either primary this year. UNH's Smith recalled then-Massachusetts Sen. John Kerry’s victory in the state 12 years ago, when Kerry overtook former Vermont Gov. Howard Dean in the polls about a week before the primary and never looked back.

“We got it dead right in 2004,” he said. “I thought I was a genius, but in reality I think I was just lucky.”