Polling

Many Fewer High Quality Polls This Year

“One reason there’s so much uncertainty in the race so close to Election Day is the sharp decline in high-quality polls this year,” Politico reports.

“FiveThirtyEight’s Nate Silver calculated the number of polls in competitive states released from Thursday evening through the day on Friday. In all, Silver counted 67 polls across 17 states.”

“That seems like a robust number, but of the 67 polls, only 5 were conducted by live telephone interviewers randomly calling voters on landlines and cell phones — still considered by many to be the most reliable form of polling.”

Trump Is Just a Normal Polling Error Behind

Harry Enten: “Even at the end of a presidential campaign, polls don’t perfectly predict the final margin in the election. Sometimes the final polls are quite accurate. An average of national polls in the week before the 2008 election had Barack Obama winning by 7.6 percentage points. He won by 7.3 points. Sometimes, however, the polls miss by more. Four years ago, an average of survey results the week before the election had Obama winning by 1.2 percentage points. He actually beat Mitt Romney by 3.9 points.”

“If that 2.7-point error doesn’t sound like very much to you, well, it’s very close to what Donald Trump needs to overtake Hillary Clinton in the popular vote. She leads by 3.3 points in our polls-only forecast.”

Four Pollsters With Same Data Had Different Results

Nate Cohn: “We decided to share our raw data with four well-respected pollsters and asked them to estimate the result of the poll themselves.”

The result? “A net five-point difference between the five measures, including our own, even though all are based on identical data. Remember: There are no sampling differences in this exercise. Everyone is coming up with a number based on the same interviews.”

Polling Averages Can Sometimes Be Misleading Too

Stuart Rothenberg: “On Election Day 2012, the RealClearPolitics polling average found incumbent President Obama “leading” Republican Mitt Romney by seven-tenths of a point – a statistical dead heat. The actual final result, an Obama victory of 3.9 points, was very different.”

“I cite these numbers not to challenge the RCP average or disparage the pollsters who got the race wrong… Still, the 2012 ‘miss’ should remind us that polling isn’t perfect and even ‘averaging,’ a reasonable strategy, can mislead. Averaging may smooth outliers, but what if one poll always seems to be an outlier, like the Los Angeles Times/USC tracking poll?”

Can We Trust the Polls This Year?

Politico: “While volatility at this stage of the campaign isn’t unexpected, the latest polling data point to an stunningly unstable election environment, unlike any in recent decades.”

Said pollster Neil Newhouse: “There’s every reason to believe that there is huge instability in the current electorate. Four years ago, there were probably 6, 7, 8 percent of voters up for grabs. Now you have 17, 18 percent up for grabs.”

Beware the Unskewers

Harry Enten: “It’s easy to find fault with a poll, even from the best pollsters. Anyone passionately arguing that a poll is wrong because its sample has ‘too many [xx]’ or ‘too many of this group are voting for [xx]’ is probably wrong. As you dig into a survey’s crosstabs — looking at college-educated white men, for example, or Hispanics 65 years or older — you’re sacrificing sample size for specificity. The margins of error of subsamples can get huge. Further, most pollsters weight their results by demographics (such as age and race) and not attitudes (like party identification). They do so because historically this has produced the most accurate result. Picking apart individual polls is usually a bad use of time, and the people doing it tend to have a motive.”

The Pollster’s Dilemma

Mark Blumenthal: “Gary Johnson and the Libertarian Party appeared on state ballots in all but two states in 2012, and Stein and the Green Party appeared on all but 12. They will likely gain access to at least as many state ballots this year, if not more. Without offering supporters of those candidates an explicit option to register their preferences, we have no practical way of tracking their support.”

“Yet if we prompt for third party candidates, many voters who are undecided about Clinton and Trump (or about voting generally) tend to grab for these alternative options as a way of indicating their uncertainty. Whatever the reason, both history and our own data yield evidence that mid-summer polls greatly inflate the true preference for third party candidates.”

Neither Is No Longer an Option

Reuters: “Many voters on both sides have been ambivalent in their support for Democratic nominee Hillary Clinton and Republican nominee Donald Trump, complicating the task of the pollsters trying to track the race.”

“That sentiment may help explain an apparent skew that recently emerged in the Reuters/Ipsos poll results. Given the choice, a relatively large group of voters opted for “Neither/Other” candidate compared with other major polls, leading to an underreporting of several percentage points for one or other of the two major contenders at times in the race.”

“As a result, Reuters/Ipsos is amending the wording of the choice and eliminating the word ‘Neither,’ bringing the option in line with other polls.”