CBS/YouGov poll: Biden and Sanders tied neck and neck going into Iowa caucuses

Hoang NguyenData Journalist
February 03, 2020, 4:30 PM GMT+0

This poll is a part of the CBS News/YouGov Tracker of convention delegates, which measures the estimated winner of Democratic convention delegates in early primary and caucus states

The Iowa caucuses are happening today—marking the first votes in the contest to decide the Democratic presidential nominee. Historically, the last four Democratic nominees have all won the Hawkeye State.

In the latest CBS News/YouGov Battleground Tracker, we asked likely caucus-voters this week for their first- and second-choice candidate preferences. We then combined this data with that on Iowa voters and take into account how the caucus system works across Iowa’s counties and districts.

The stakes are high—and our recent poll shows that the race is tight going into Monday. Joe Biden and Bernie Sanders sit even in first-choice support at 25 percent each, followed by Pete Buttigieg (21%), and Elizabeth Warren (16%). Amy Klobuchar is the only other candidate who garners at least five percent of the first-choice votes.

Methodology: This CBS News survey was conducted by YouGov between January 22 to 31, 2020. The multilevel regression model incorporates individual-level and district-level variables, such as age, race, gender, education, party registration, and vote history. Vote intentions were imputed onto voter file records in Iowa and then aggregated statewide and by district. The margin of error on these estimates is ±3 points. It reflects the range of uncertainty around the estimates produced from the model simulation.

The model partially pools data across states including Iowa, estimates effects for each state and district in the sample, as well as a linear time trend. Estimation of voting intentions is based on surveys conducted for the Battleground Tracker project, including a sample of 1,835 registered voters in Iowa and a nationally representative sample of 34,375 registered voters from YouGov.

Of respondents who participated in the previous wave of Iowa polling from January 16-23, 2020, 538 were re-interviewed for this study — a recontact rate of 29%. Respondents were selected to be representative of registered voters within Iowa. 732 were selected from YouGov's panel, and 1,103 from other online panels (Critical Mix, Dynata, Lucid and Precision Sample). All candidates were shown to respondents to express their first and second choices.

Using estimated vote intentions, we simulate the number of delegates going to each candidate by district and statewide. Following party allocation rules, candidates with less than 15 percent of the vote in a district or at large are eliminated, and delegates are awarded to remaining candidates in proportion to their vote shares.

Delegate estimates indicate how many delegates each candidate would receive based upon preferences respondents currently express. They are offered to explain how vote preferences translate to delegates under party rules and are not a forecast — the model does not incorporate forward-looking uncertainty. Read more about the process and the Battleground Tracker here.

Explore more data from CBS/YouGov polls

Graphics courtesy of CBS News and cover image courtesy of Getty.