The 2020 Democratic Iowa Caucuses: Final Update

[Eds. note: This post was updated at 4 pm EST on February 3, 2020 to reflect on final Iowa Caucuses poll.]

At 7 PM Iowa time (8 pm EST) on February 3, 2020, Iowans will gather in nearly 1,700 precinct-level meeting places to support their preferred candidate to be the 2020 Democratic presidential nominee. They will also participate in a range of party-related business that does not concern us here.

With the exit of former Member of the United States House of Representatives (“Representative” from Maryland John Delaney on January 31, 2020, there are now “only” 11 remaining declared candidates to be the 2020 Democratic presidential nominee. The 17 candidates who have abandoned this quest have done so with grace, class and dignity; I commend them for it.

To learn how I calculate candidate WAPA (weighted-adjusted polling average), please see here; for modifications, please see here.

Here is a photograph of the Iowa Visitor’s Center on I-80 in Rock Island I took on September 5, 1990:

Iowa Visitor Center Sep 1990


As of 4:00 pm EST on February 3, 2020, here is a breakdown of publicly-available Iowa Caucuses polls:

  • 59 since January 1, 2019
  • 46 since the 1st Democratic debate on June 26, 2019
  • 22 since the 5th Democratic debate on November 19, 2019
  • 16 since the 7th Democratic debate on January 14, 2020

Before I present my final pre-Caucuses WAPA, however, here are some words of caution.

1. Caucuses differ in key ways from primaries

In the Iowa Caucuses, voters gather in a public space to publicly declare their support for a candidate. As in, they literally divide into groups of supporters for former Vice President Joe Biden, United States Senator (“Senator”) from Vermont Bernie Sanders, Massachusetts Senator Elizabeth Warren, former South Bend, IN Mayor Pete Buttigieg, Minnesota Senator Amy Klobuchar, and so forth.  A head count is taken; this initial tally is, in effect, what pre-Caucuses polls measure. This tally has never been reported.

However, any candidate whose supporters do not comprise 15%[1] of all voters at a caucus site is deemed not “viable,” and that candidate’s supporters now must choose a new, viable candidate (or, “uncommitted”). Representatives of viable candidates attempt to persuade their friends and neighbors to caucus with them; there are already stories of candidates attempting to form “alliances” in the days leading up to the Caucuses.

Once every candidate is viable, a final tally is taken. This tally has also never been reported. Why? Because the actual purpose of these precinct-level caucuses is to identify delegates to county-level conventions, which then identify delegates to the state convention, which then identifies the 41 delegates to the Democratic nominating convention to be held in Milwaukee, WI from July 13 to July 16, 2020. Thus, what has always been reported are a projection of what percentage of those 41 delegates will be pledged to vote for each candidate at the national convention; these are known as “state delegate equivalents,” or SDE’s.

This year, though the Iowa Democratic Party has announced it will report three values Monday night (or Tuesday morning):

  • The initial statewide tally for each candidate
  • The post-viability tally for each candidate
  • SDE’s for each candidate

It is thus conceivable, if not especially likely in my opinion, there will be three different “winners” of the Iowa Caucuses—or at least, confusion over the order of finish. What is still very likely, is that only three-five candidates will get any sort of boost out of Iowa.

One other way in which caucuses differ from primaries is much lower turnout, which is especially harder to forecast with any accuracy. For example, 171,517 Democrats participated in the 2016 Iowa Caucuses, while 653,669 Iowans voted for Democratic presidential nominee Hillary Clinton that fall; general election data from Dave Leip’s invaluable Atlas of U.S. Presidential Elections. Caucus turnout was thus 26.2% of general election turnout, roughly speaking. That’s year’s New Hampshire Democratic Primary—usually a relatively high-turnout event—had 253,062 participants, fully 72.6% of that state’s vote total for Clinton.

2. Absent poll numbers

There have been fewer polls of the Iowa Caucuses this year than in any election cycle since 2004: 19 in the previous month, compared to an average of 24 during the same period in 2008-16. But one poll’s absence is more glaring than the rest: the gold standard of Iowa Caucuses polls, the Des Moines Register Iowa Poll conducted by Ann Seltzer, which rates A+. The Register, in conjunction with CNN, had planned to release its final Iowa Poll at 9 pm EST on February 1, 2020. However, due to the apparent absence of Buttigieg from the list of names read to at least one poll respondent, the poll was cancelled.

This poll would have had a weight of 0.987, edging out a Monmouth College poll conducted January 23-27, 2020 (0.977) and a Siena College/New York Times poll conducted January 20-23, 2020 (0.970), for highest weight overall. My Twitter feed is filled with rumors as to what the results of the poll would have been, from a massive surge by Sanders to a surge by Warren. I would not put much credence into any of these rumors.

Well, except for one thing. Three polling firms, Emerson College (A-), David Binder Research (C+) and Civiqs (C+) have conducted multiple polls of the Iowa Caucuses in the last three weeks. Using the most recent pair of polls, here are average changes ranked from highest to lowest:

  • Buttigieg  +2.0 points
  • Sanders  +1.7
  • Warren  +0.7
  • Bennet, Patrick  no change
  • Gabbard, Yang -0.7
  • Steyer  -1.3
  • Klobuchar -1.7
  • Biden -3.0

Finally, former New York City Mayor Michael Bloomberg has been excluded from eight of the 16 Iowa Caucuses conducted entirely after the 7th Democratic debate; he averages 1.1 percentage points (“points”) in the seven polls which include him.

3. The Des Moines Register endorsement

Iowa’s largest newspaper still commands attention, particularly among undecided or not-fully-committed caucus-goers. According to, the last five Democratic candidates endorsed by the Register in competitive races—1988, 2000, 2004, 2008, 2016—saw Iowa Caucuses results a median 6.0 points higher than their polling average at the time of the Register endorsement. That value drops to 4.3 if you include only data from 2000 forward. The average value, meanwhile, was an increase of 8.5 points, but that drops to 5.3 when you exclude the astonishing 21.6-point increase for North Carolina Senator John Edwards in 2004. Still, even the 2.1-point increase for Clinton in 2016 could matter in a very close contest.

On January 25, 2020, the Register endorsed Warren. This was just six days after the New York Times endorsed both Warren and Klobuchar. As you see in Table 1 below, the race in Iowa has been close for months, though there is evidence Biden and, especially, Sanders have pulled slightly ahead. Still, Warren went up in those two recent polls, and another late poll—from Data for Progress (B+/C-), January 28 to February 2, 2020—gives her 19% of the vote. Thus, a minimum 4.3-point increase for Warren is highly plausible. If it comes primarily at the expense of Sanders and Biden, it could make the difference between Warren finishing in a close top two or a more distant fourth…or even fifth, behind Klobuchar.

Table 1: Final Iowa Caucuses WAPA for declared 2020 Democratic presidential nomination candidates

Candidate All Polls Since 1st Debate Since 5th Debate Since 7th Debate
Biden 19.8 19.7 19.9 20.0
Sanders 18.4 18.8 20.9 22.4
Warren 17.1 18.1 15.6 15.5
Buttigieg 16.0 16.9 16.7 16.8
Klobuchar 7.0 7.4 9.1 9.8
Yang 2.9 3.2 3.5 3.7
Steyer 2.8 3.1 3.1 3.5
Gabbard 1.6 1.6 1.6 1.6
Bloomberg 0.4 0.4 0.6 0.5
Bennet 0.3 0.3 0.2 0.3
Patrick 0.0 0.0 0.0 0.1
DK/Other 13.7 10.5 8.7 5.7

The bottom line is this: anybody who thinks they know what will happen in the 2020 Iowa Caucuses has absolutely no idea what will happen in the Iowa Caucuses. The polling, already very difficult to do in a multi-candidate race, is extremely close—with fully four candidates above the 15% viability threshold (and a fifth not far behind), at least statewide; we have almost no sense of caucus-goers’ “backup” choices, or even who will participate; and we are lacking the definitive poll of this race. Perhaps Sanders and Biden really do have a slight edge over Warren and Buttigieg, but I would not bet anything remotely of value on it; in fact, I think Warren’s chances of finishing first or at worst a very close second are understated.

We shall see.

Until next time…

[1] Without rounding, I believe.

Published by

Matt Berger

I am a data geek, writer, investigator and film noir devotee with academic training in political science (Yale BA, Harvard MA), biostatistics (Boston University SPH MA) and epidemiology (Boston University SPH PhD). In January 2021, I finished writing Interrogating Memory: Film Noir Spurs a Deep Dive Into My Family History...and My Own for which I seek literary representation and a publisher. In Chapter 6: So...What Is Film Noir, Again?, I analyze my film noir database, which contains 4,825 titles. My musical holy trinity is Genesis, Miles Davis and Stan Ridgway. I am a liberal Democrat who understands a thriving democracy requires at least two mature political parties. I grew up just outside Philadelphia, and I live just outside Boston, where my wife and daughters keep me happy, sane and grounded. Please ask me anything else you want to know.

3 thoughts on “The 2020 Democratic Iowa Caucuses: Final Update

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s