The poll out Saturday night found Warren was the top choice for the Democratic nomination with 22 percent support among likely caucus-goers, while Biden had the support of 20 percent of respondents. Vermont Sen. Bernie Sanders fell to third with 11 percent.
The poll was conducted of 602 likely Democratic caucus-goers from Sept. 14-18. The margin of error is plus or minus 4 percentage points.
The last Register/CNN poll, in June, had Biden leading with 24 percent and Warren in the third spot at 15 percent, slightly behind Bernie Sanders, who came in second with 16 percent support.
While there have been several other recent polls of the crucial first-in-the-nation caucus state, the Des Moines Register's Iowa Poll, conducted by Des Moines-based pollster Ann Selzer, is widely considered to be the most accurate, so its Saturday night releases have become must-watch events for Iowa politicos.
The poll was released after the entire 2020 Democratic presidential field gathered in Des Moines Saturday for the annual Steak Fry, a fundraising event hosted by the local Democratic Party club.
Warren surged 7 points in the poll since the June survey, while Biden lost a bit of ground, putting them neck-and-neck inside the poll’s margin of error.
Sanders and Mayor Pete Buttigieg of South Bend, Indiana, both slipped significantly, down 5 and 6 percentage points, respectively, leaving Buttigieg at 9 percent, down from 15.
The rest of the field, meanwhile, is mired in the single digits.
California Sen. Kamala Harris held steady at 6 percent, New Jersey Sen. Cory Booker gained a couple of points to land at 3 percent, while coming at 2 percent were Minnesota Sen. Amy Klobuchar, former Texas Rep. Beto O’Rourke, billionaire Tom Steyer, Hawaii Rep. Tulsi Gabbard and entrepreneur Andrew Yang. Everyone else was at 1 percent or below.
Still, just one-in-five likely Democratic caucus-goers said they had already made up their minds so the race remains fluid. Almost two-thirds said they were open to being convinced to support someone else.
“The data in this poll seem to suggest the field is narrowing, but my sense is there’s still opportunity aplenty,” Selzer told the Register. “The leaders aren’t all that strong. The universe is not locked in.”
But the data is unquestionably good news for Warren, who is now both the best-liked candidate in the field (75 percent view her favorably) and the candidate being considered by the most likely caucus-goers (71 percent).