Since the 1980 presidential race, Democrats have done markedly better than Republicans with women voters. This is known as the gender gap. But primaries can produce gender gaps too, with men and women of the same party voting differently. For example, in the 2020 Democratic primary, Vermont Sen. Bernie Sanders did consistently better with men than women in polls.

Should we expect a gender gap in Iowa today? Possibly. It varies, but some polling evidence from December suggests that Iowa women are more likely than men to favor Trump. An Iowa State University poll of likely GOP voters has 58 percent of women and 51 percent of men selecting Trump as their first choice. Similarly, a Fox News poll has 56 percent of women and 49 percent of men selecting Trump as their first choice. But a CBS News poll shows a smaller gap, that's flipped — 59 percent of men and 57 percent of women say Trump is their top choice. Trump's lead among women is somewhat surprising in the larger context. In the 2016 general election, we saw a large gender gap because Trump did well with white men, but lost women (relative to Romney's performance in 2012). And much has been written about his struggle to win over suburban women, and young women, too. However, primary voters are unique, and Trump's brand of conservatism isn't putting off these women. In the 2016 Iowa caucuses, Trump won 25 percent of men and 24 percent of women (according to entrance polls).

Another interesting finding is that the polling does not suggest gender affinity — that is, individuals being more likely to support political candidates of their same gender — is at play in Haley's numbers. The concept of gender affinity is rooted in the idea that shared gender identity can lead to perceived commonality in experiences, perspectives and priorities. Haley's pitch hasn't necessarily been aimed at the women in her party, although she does emphasize gender as she campaigns. But overall, Haley tended to do slightly better with men than she does with women in those same Iowa polls, a pattern also present in national polls.

DeSantis, on the other hand, has made a more concerted effort to court women voters, but the polls from Iowa don't suggest those efforts have worked. In none of the aforementioned polls is DeSantis winning women, and in only the CBS poll does he poll better with women compared to men (25 percent of women and 20 percent of men pick DeSantis as their first choice).

Hello! I’m Meredith Conroy, a politics contributor at 538. I’m a political scientist at California State University, San Bernardino, who studies the role of gender and media in American politics. Tonight, I’ll bring a political science perspective to the conversation (probably in the form of links to academic articles that are too long). I’ll also be watching closely to see where (and among whom) Haley is performing well. She’s got most of her eggs in the New Hampshire basket, but could claim a moral victory in Iowa if she can stay competitive with DeSantis.

In Iowa tonight, our delegate benchmarks suggest Trump needs to win just 12 of 40 delegates to be on track to win the overall majority by July. To do so he will need 30 percent of the vote (our average of polls has him getting 53 percent). Meanwhile, DeSantis and Haley need to win 22 and 26 delegates, respectively, in order to be on track to win the nomination. Either would have to beat their polls dramatically to win such tallies.

The difference in these projections boils down to where the candidates draw their strength from. Our model looks at polling, demographics and political data in every state to project how many delegates we can expect each candidate to win from every contest. We then adjust candidate support in each state until those projections add up to a majority of delegates — the threshold needed to win the nomination. DeSantis and Haley are more popular with moderate, college-educated and anti-Trump voters, who are overrepresented in early states. That means they need lots of delegates from those states to win. In contrast, thanks to strength among non-white and evangelical Republicans, Trump is projected to do better in states that vote later in the primary calendar. That means he can stay on track to win even with a poor performance, compared to his polls.

Of course, the outcome of tonight’s caucuses will also alter the shape of the race. For example, a bad showing for Trump could catapult his rivals to success in later states. Our benchmarks are not forecasts for those contests. Once we have results from each contest, or the polls change significantly, we will update our benchmarks for future states.

According to a January Selzer & Co./Des Moines Register/NBC News/Mediacom survey, 34 percent of likely Republican caucusgoers say they will be voting in the Iowa caucuses for the first time, while 66 percent say they have attended at least one caucus in the past (Republican, Democratic, or both). Throughout the campaign, Selzer polls have shown steady growth in the number of likely voters that say they are first-time caucusgoers, increasing 15 percentage points from the first time the question was asked in August 2023.