I just want to underscore Elliott's point about how hard polling has gotten with a quick story I wrote up in a paper with Tori Gorton called "On the Internet, No One Knows You're An Activist." We were trying to survey lower-engagement voters, so we drew a sample of 9,937 registered Pennsylvania voters who hadn't consistently voted 2012-2018. Then, we matched them to Facebook accounts and served ads to 1,321 inviting them to take a survey. 66 people clicked on our ad, 7 began the survey, 6 completed it, and 1 person left an email for follow-up. I of course want to express my deep gratitude to that one respondent. But beyond that, a 0.4% response rate magnifies sampling errors, because very small differences in people's willingness to take polls can add up to very large errors in vote margins. That's especially true in primaries, where pollsters can't use partisan identification to stabilize the results.

—Dan Hopkins, 538 contributor

We've been tracking Trump's non-incumbent endorsees (because endorsing the incumbent is kind of a gimme) tonight, and so far he's 4 for 4 of the races called. Addison McDowell, Trump's pick in North Carolina's GOP primary for the 6th District, is also leading. But in California, state Assemblyman Vince Fong, who received Trump's endorsement for the Republican primary in the state's 20th District (Kevin McCarthy's old seat), is trailing at 26 percent with 23 percent of the expected vote reporting.

—Kaleigh Rogers, 538

It has become somewhat of a theme of our live blogs this primary calendar to note that Trump's challengers are beating their polls. This first looked to be the case in New Hampshire, where polls significantly underestimate support among Republican likely voters for Haley. But the pattern is more robust than one state: In fact Haley has been beating her polls by an average of five points (in vote share) once you account for undecided voters in these surveys. The consistency of this pattern is striking enough to warrant a post on the matter.

As Mary said earlier, polling primaries is hard! That is betrayed by the fact that POTUS primary polls are by far the least accurate type of poll in 538's pollster rating database going back to 1999. But error is different than bias, and when most of the polls are off in the same direction, something has gone awry.

That "something" is likely the difficulty in obtaining opinions of moderate Republicans from samples of "likely Republican primary voters." Remember that fewer than one percent of people called for a poll actually complete the interview. That means the ones that do are statistical "weirdos" (excuse the technical language). Pollsters adjust for this by weighting their samples to known population benchmarks — like the percent of all adults who are white, over 65, have a college education etc. But in primaries, such benchmarks do not actually exist; pollsters are just making educated guesses about them.

My theory is that most of these primary polls pulling samples of voters from voter registration lists are missing moderate crossover partisans and first-time voters. Additionally, we know that people who are highly motivated to participate in polls (the "weirdos") also happen to be the most politically and ideologically extreme Americans. That's a recipe for polling bias in primaries, where weighting to party, past vote and polarized demographic benchmarks does not control for the partisan consequences of overrepresenting politically engaged Americans.

Now, none of this is to say that polling is "broken." It's just hard to precisely sample a population that doesn't really exist. The polls for the 2024 primary still have below-average error, historically speaking, so we shouldn't go throwing out the baby with the bathwater. But this could nevertheless be a sign of pollsters having a hard time reaching moderate "normie" voters. And if that persists, it could have consequences for general election polls too.

—G. Elliott Morris, 538

In California's 40th District, with 46 percent of the expected vote in according to the Associated Press, engineer Allyson Damikolas (endorsed by EMILY's List), is trailing former fire captain Joe Kerr (endorsed by the Congressional Progressive Caucus PAC). The 40th is a key target for Democrats, who are looking to win back some of the ground they gained (and then lost) in the Orange County area. The 40th District spans Riverside and San Bernardino Counties, too.

—Meredith Conroy, 538 contributor

As the Super Tuesday results come in, there will be a lot of attention to how they compare with the 2016 primaries. In early voting states such as Iowa and New Hampshire, Trump has tended to do better in the places where he did well eight years ago. But we should be careful not to overstate the continuity. While Trump was seen as a relatively moderate Republican back in 2016, he now anchors the conservative end of the political spectrum.

In January 2016, Diana Mutz and I asked a population-based panel of Americans 26 and older whom they supported in the GOP presidential primary. Back then, Trump's best group of GOP primary voters were actually those who called themselves "moderates," while Ted Cruz won respondents who said they were "extremely conservative." Later that year, we asked all respondents to place Trump on a 7-point ideology scale, where "1" meant "extremely liberal" and 7 meant "extremely conservative." Trump scored 5.0, placing him almost exactly at "slightly conservative."

But after Trump had been president for three years and had overseen major tax cuts and an effort to repeal the Affordable Care Act — not to mention being the face of a growing contingent of MAGA-inspired conservatives — perceptions of him had changed. In January 2020, our panelists rated him a 5.6, meaning they saw him as closer to "conservative" than to "slightly conservative."

Other data reinforces the idea that perceptions of Trump continued to shift, and that he shed the perception of being a moderate. In April 2021, I teamed up with Hans Noel to ask political activists who was more conservative among pairs of prominent politicians. From those comparisons, we generated perceived ideology scores. By then, Trump was perceived by all respondents to be fairly far on the conservative end of the spectrum, with just ten GOP politicians to his right versus 43 to his left. (The Republicans who were perceived to be on his right are generally seen as Trump allies, such as Sens. Tommy Tuberville, Josh Hawley and Tom Cotton.) It's noteworthy that at the time, Nikki Haley was ranked just two slots less conservative than Trump.

Noel and I replicated the analysis in November 2023 in a YouGov survey of American adults. Among Republican survey respondents, Ron DeSantis was thought to be the second most conservative figure, with only Ted Cruz viewed as more conservative. But Trump was also far on the conservative end of the spectrum, ranking fifth out of 23 Republicans on the list. It's no surprise that in that same survey, Trump's best group for the primary was respondents who called themselves "very conservative."

Haley, by contrast, had come to be seen as closer to the center of the GOP — she was viewed as more conservative than Mitch McConnell, Chris Christie and Kevin McCarthy, but also more liberal than fellow primary candidates Vivek Ramaswamy and Mike Pence, and Trump allies like Hawley and Sarah Huckabee Sanders. Haley's best group in the November survey was self-described "moderates," although Trump still won that group with 51 percent compared to Haley's 18.

That reflects the fact that DeSantis and Haley cut somewhat different profiles among GOP primary voters. While Haley is the Trump challenger still in the race, DeSantis seems to have been the bigger threat to the conservative base that Trump has come to rely on. And with DeSantis out of the race, Trump has been able to consolidate the GOP's conservative wing, which has increasingly been defined by his politics since 2016.

—Dan Hopkins, 538 contributor