Can we trust polls? It depends on how much you trust them.
Even the most carefully conducted polls are imprecise snapshots of public opinion, not precision instruments – and when forced into predictive tools, they don’t always get it right. But while polls can’t provide an unambiguous answer about who wins in close races, they often paint a clear and important picture of the political landscape.
The edges of some results are sharp enough to be visible even through the shadows of potential query errors. Poll after poll shows President Donald Trump’s approval rating is between 35 and 35 nationally. Surveys also show broad consensus that Americans, rattled by concerns about the cost of living, have a largely dim view of the economy and Trump’s handling of it; that there is little enthusiasm anywhere about the current state of the nation; and that voters are overwhelmingly looking for change — even if they don’t all agree on precisely what that change should look like.
Likewise, the Democrats’ lead in the national “wildcard poll” has been consistent and strong enough to suggest that the party has an overall advantage — and it would take an unprecedented level of polling error to overcome that advantage. But there is much less certainty about the precise level of this advantage, or how it might manifest in individual races. Even a small difference in Democratic strength from what polls suggest could mean the difference between a blue wave that sweeps largely into Republican territory and one that fails to overcome a deeply Republican-friendly Senate map.
One thing that poses a challenge for pollsters this year is that there is another finding that appears to be both a determining factor in the race and a potential source of polling error: the yawning gap in partisan enthusiasm for voting.
The polls – consistent with early voting data – revealed that, compared to Republicans, Democrats say they are much more motivated to vote this year. This plays a role both in pollsters’ efforts to get people to respond to polls and in their attempts to identify potential voters who will end up voting in this election.
According to Gallup, the Democratic enthusiasm advantage is the largest on record in a midterm since 1994. Part of the reason is that, especially in his second term, Trump is generating far more fervent opposition than ardent support. This is also partly due to the growing education gap in American politics, with college-educated voters more likely than those without a degree both to run in the midterms and to vote Democratic if they do.
But that same enthusiasm divide could also influence voters’ willingness to respond to polls.
In a Washington Post-Schar School poll in Kansas, for example, registered Democrats who were contacted by pollsters were far more likely than registered Republicans to respond to the survey. While this disparity has not been universal this cycle, the latest round of polling from The New York Times and Siena College also revealed a similar response pattern.
This type of variation, sometimes called “differential nonresponse,” does not pose an entirely new challenge for pollsters. Certain types of people have always been more likely than others to respond to surveys, including older people, those with higher levels of education, and those who are more civically engaged. Pollsters correct for this disparity by weighting their results so that the demographics of their sample more closely resemble the broad universe of people they are trying to measure. Increasingly, this also includes weighting based on known partisan goals, such as party registration levels in a state or vote choice in the 2024 election.
What pollsters worry about are trends that aren’t fully corrected, even after weighting for demographic and partisan goals. A poll might have the “right” number of Republicans and Democrats to reflect the electorate, but not reach the right mix of voters within each party.
Not all registered voters vote in every election — most years, 40% or more don’t vote — and that can also complicate the situation for pollsters. To reflect the opinions of those who ultimately turn out, pollsters identify potential voters, and these efforts can be complicated by the same factors that make it difficult to reach less enthusiastic potential voters.
It’s possible that certain types of Republicans are too disengaged to respond to polls, but nonetheless motivated enough to end up voting – or that the most engaged and enthusiastic Democrats are overrepresented in polls.
Even if the polls accurately reflect the dynamics at the time they were conducted, there is still room for change after the poll is completed if Republican voters late rally around their candidates.
CNN’s latest state polls, for example, gave voters the opportunity to say they wouldn’t support either candidate in the upcoming Senate race — and even after being asked a follow-up question about which direction they would lean, 6 to 8 percent in each poll said that, between the two major candidates, they would support “neither” or anyone else. The poll also pushed voters to choose which party they would prefer to see control the Senate, even if they initially said it didn’t matter to them. Examining these two questions together shows us that in most of these polls, voters who favored control of the Republican Party were more likely than those who preferred to see a Democratic victory to forgo the choice of a major party candidate – by about 9 points in Texas, 6 points in Kansas, and 4 points in Michigan.
This could well reflect what happens on Election Day. The Republican candidates in Texas and Kansas, Ken Paxton and Roger Marshall, face specific image problems that have made it more difficult for them to consolidate their party’s support, and it is entirely plausible that Republican-leaning voters in those states will end up passing up the race. But it also suggests that Democrats haven’t closed the deal yet.. In a series of relatively close races, this could be enough to significantly reduce the margins or completely change the outcome of some races.
On the other hand, it is not certain that a failure in the polls would favor the Democrats. Presidential polls in the last three cycles have underestimated Republican vote share relative to Democrats: by about 3 points in 2016 and 2024, and by almost 5 points in 2020.
But there was no similar pattern in the Trump-era midterm elections. Nor is it guaranteed that missed elections would look the same in the many states in play.
As we wrote in 2024, polling data is a unique and imperfect indicator of people’s opinions. But U.S. polling, ultimately, is a way to engage with Americans from a wide range of demographics, life experiences, and opinions, on topics that go far beyond elections, or even politics. In a society that is deeply fragmented and where social media often reflects an unrepresentative sample of the loudest voices, it remains a valuable tool for understanding the country as a whole.
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