Former Vice President Joe Biden continues to lead the crowded Democratic field — but under a “ranked-choice” system designed to suss out the majority’s ultimate preference, Sen. Elizabeth Warren would top Biden, 53 percent to 47 percent, according to a new poll exclusively provided in advance to Vox.

The online national poll of likely Democratic voters was conducted by YouGov, and sponsored by FairVote, a nonpartisan advocacy group supporting electoral reform. Unlike an ordinary poll, it asked respondents to rank several candidates in order of preference — so as to simulate ranked-choice voting, a system currently used in Maine and other localities. (FairVote advocates in favor of the system and hopes it will be adopted elsewhere in the US as well.)

The way ranked-choice voting works is that candidates with fewer votes are eliminated, and then their votes are redistributed to whomever each voter designated as their next-ranked preference. For instance, a voter could rank Sen. Bernie Sanders as their first choice and Warren as their second choice — meaning that, if Sanders was eliminated, this vote would be transferred to Warren.

YouGov tested the ranked choice methodology offering all 20 remaining Democratic candidates as options (with the ability to rank 10 of them) — and also by just offering the current top five candidates (Biden, Warren, Sanders, Sen. Kamala Harris, and South Bend, Indiana, Mayor Pete Buttigieg) as options. The end results were quite similar for both versions, so this article will focus on the five-candidate version for simplicity’s sake. (The more extensive results for both versions are available at FairVote’s website.)

In an initial tally counting only voters’ top-ranked choices, Biden leads the Democratic field with 33 percent, and is followed by Warren with 29 percent, Sanders with 20 percent, Harris with 10 percent, and Buttigieg with 8 percent, per the poll.

But it turns out that respondents who initially favored Sanders and Harris prefer Warren over Biden, by about a two-to-one ratio. So once the field is narrowed to a head-to-head matchup of just Biden and Warren, and votes for the eliminated candidates are to whomever each voter ranked higher, Warren would lead Biden by 6 points.

The results are an interesting indication of how an outcome can change due to a different tallying system. But they could also be indicative of something bigger.

Though voters theoretically can choose among many of candidates, we are still months away from a day when primary voters will cast votes. So how voters rank their options in a smaller field could tell us a lot about what the race might look like in the future, and what might happen were the field to winnow further. These results, at least, suggest that Warren would benefit more than Biden would.

Walking through the ranked-choice results

To the uninitiated, ranked-choice voting (sometimes called “instant runoff voting,” or IRV) might seem like a confusing and convoluted system. Our respondents were asked to rank Biden, Buttigieg, Harris, Sanders, and Warren by preference — from first choice, to second, to third, to fourth, to fifth. (If they wouldn’t vote for some of these candidates at all, they could notate that as well.) The graphic below walks through the tally.

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