For all of the legitimate (and occasionally overblown) hand-wringing about “horse race” coverage of national politics, it is a lamentable fact that horse racing generally offers a good analogy for polling.

I’ve made this point before, but it’s worth rehashing. Polls can be thought of like snapshots of a horse race. They show who’s leading and by how much. Compare the snapshot with a prior picture, and you can see which horses have moved ahead and which haven’t. And, of course, the snapshot shows how far along the race is. A photograph of horses jostling on the backstretch offers insight into who’s doing what — but it’s still just the backstretch. A picture of the field coming into the homestretch is something else entirely.

On Tuesday afternoon, Monmouth University gave us a new snapshot of the race for the Democratic presidential nomination in Iowa. It shows a three-person race, with South Bend, Ind., Mayor Pete Buttigieg joining Sen. Elizabeth Warren (Mass.) and former vice president Joe Biden at the top of the field. Sen. Bernie Sanders (I-Vt.) trails just behind.

It’s a big change for Buttigieg who, in Monmouth’s August poll, was under 10 percent. He’s improved by 14 points, ignoring the role of margins of error for the moment.

That’s going to be the focal point of a lot of coverage of the new poll, and understandably so. But the snapshot we were handed was something like a picture of a crowded field on the stretch turn, a number of horses, any of which have some shot at crossing the line first. Buttigieg joined the pack, but it remains to be seen whether he can keep running with them.

One indicator that he can is that he’s the combined first or second choice of 37 percent of likely caucusgoers. That’s about where Warren is, at 35 percent. Warren’s position on that metric has held steady since August, when she was the first or second choice of 38 percent of Iowans. Biden dropped from 38 percent, then to 29 percent now.

It’s important to remember, too, that this isn’t a normal race. It’s not simply that each candidate is racing to cross the finish line and the person with the most support earns the delegates. Instead, the Iowa caucuses use a threshold underneath which support gets redistributed. That’s where the second-choice question becomes particularly significant: If Sanders doesn’t get 15 percent support at a caucus site, for example, his supporters have to go to another candidate. Being the most popular second choice means more in Iowa than it does elsewhere.

That system does admittedly break our horse-race analogy.

What’s particularly notable in Monmouth’s poll is the factor highlighted by the pollsters themselves, who published their results under the headline, “Few Caucusgoers Tied to 2020 Choice.” The race is very fluid, and a lot of people indicate that they’re willing to change their minds.

Specifically, only about a third of respondents say that they’re firmly committed to a candidate or that there’s only a low possibility they’ll change their minds. About half say they’re more flexible. That sort of flexibility is what leads to 14-point jumps in the polls.

(It’s worth noting that Buttigieg, in addition to earning the most support, was the candidate most likely to be identified as someone voters had seen in person. A third of respondents said they’d seen a candidate in person. Seventeen percent said they had seen Buttigieg. By contrast, 11 percent said they had seen Biden.)

Buttigieg also probably benefits from not being the target of much negative attention from his opponents. His net favorability (those who view him favorably minus those who don’t) remained high since August. Biden and Warren both saw their net favorabilities drop. In Warren’s case, that’s probably partly a function of how much fire she took at the most recent Democratic debate, itself a function of her surge in the polls.

This, too, doesn’t translate well to our horse-race analogy. The horse in the lead is … the target of people throwing rotten fruit or something? As they race to a finish line at which point the trailing horses have to join the leading horses’ teams? Is that right?

The Monmouth poll also undercuts that analogy in the most direct way. At any given moment, the position of half the horses in the field could just suddenly change dramatically. It’s like a horse race with changing rules taking place on a flood plain during a monsoon. A snapshot of what’s happening is by no means useless, but it takes about six minutes of explanation before you can understand what you might be looking at.