2020 New Hampshire Primary: How did my polling averages fare?

Given the extremely volatile polling for the 2020 Democratic presidential nomination following the start of primary and caucus voting, I will not provide global monthly updates for the next few months. Instead, I will focus on the first handful of primaries and caucuses: Iowa on February 3, New Hampshire on February 11, Nevada on February 22, South Carolina on February 20, the 14 Super Tuesday contests on March 3, and so forth.

Also: I now weight higher polls conducted partially (1.33 or 1.67) or entirely (2.00) after February 3, 2020, than polls conducted entirely before February 4, 2020. I similarly weight higher polls conducted partially (2.33 or 2.67) or entirely (3.00) after Feb 11, 2020.

Unlike the molasses-slow pace it took for results from the 2020 Iowa Caucuses to be released—ultimately leading to the resignation of Iowa Democratic Party Chair Troy Price—95+% of the results from the 2020 New Hampshire Primary were tabulated and released within five hours of the final poll closings at 8 pm EST on February 11, 2020.

This improvement is undoubtedly due to the two “sharing size” bags of M&M’s—one plain, one peanut—I purchased at our local CVS after dropping our eldest daughter at her swim team workout. These candies have long been a staple of our election night watch parties, yet I neglected to buy some for the Iowa Caucuses the previous week.


Earlier that day, meanwhile, I had published my final New Hampshire Primary WAPA (weighted-adjusted polling average) for the 11 then-declared Democratic presidential candidates, calculated five different ways (Table 1):

  • 71 since January 1, 2019
  • 57 since the 1st Democratic debate on June 26, 2019
  • 35 since the 5th Democratic debate on November 19, 2019
  • 27 since the 7th Democratic debate on January 14, 2020
  • 15 since the Iowa Caucuses on February 3, 2020
    • 14 starting February 4 or later
    • 1 (Monmouth University) on February 3

Table 1: Final New Hampshire Primary WAPA for declared 2020 Democratic presidential nomination candidates

Candidate All Polls Since 1st Debate Since 5th Debate Since 7th Debate Since


Sanders 23.0 23.1 24.8 25.5 26.4
Buttigieg 16.7 17.0 18.8 19.4 21.4
Biden 15.8 15.3 14.0 13.0 12.2
Warren 14.3 14.7 12.9 12.6 13.1
Klobuchar 7.0 7.2 8.6 9.3 9.7
Gabbard 3.4 3.5 3.7 3.5 3.2
Yang 3.2 3.3 3.6 3.4 3.2
Steyer 2.5 2.6 2.9 2.8 2.6
Bennet 0.4 0.5 0.5 0.5 0.6
Bloomberg 0.3 0.3 0.4 0.3 0.1
Patrick 0.3 0.3 0.4 0.4 0.4
DK/Other 13.1 12.2 9.6 9.2 7.1

Based solely on these numbers, one could reasonably draw the following conclusions:

  • United States Senator (“Senator”) from Vermont Bernie Sanders; former South Bend, Indiana Mayor Pete Buttigieg; and Minnesota Senator Amy Klobuchar were rising in the polls heading into the Iowa Caucuses.
  • Former Vice President Joe Biden and Massachusetts Senator Elizabeth Warren were declining in the polls.
  • No other candidate was moving in the polls one way or the other.

Comparing WAPA to results. Table 2 lists the results of the 2020 New Hampshire Democratic Primary as of 2 am EST on February 13, 2020:

Table 2: Percentage of vote received in 2020 New Hampshire Democratic Primary

Candidate % Vote
Sanders 25.8
Buttigieg 24.5
Klobuchar 19.9
Warren 9.3
Biden 8.4
Steyer 3.6
Gabbard 3.3
Yang 2.8
Write-in votes (including Bloomberg) 1.4
Patrick 0.4
Bennet 0.3
All others 0.4

Table 3 lists the arithmetic differences between each candidate’s final Iowa Caucuses WAPA and each of the three reported measures; positive values indicate better performance in the Caucuses than in the polls.

Table 3: Arithmetic difference between Vote % and WAPA, 2020 New Hampshire Democratic Primary

Candidate All


Since 1st Debate Since 5th Debate Since 7th Debate Since




Sanders 2.8 2.7 1.0 0.3 -0.6 1.2
Buttigieg 7.8 7.5 5.7 5.1 3.1 5.8
Biden -7.4 -6.9 -5.6 -4.6 -3.8 -5.7
Warren -5.1 -5.5 -3.7 -3.4 -3.9 -4.3
Klobuchar 12.9 12.7 11.3 10.6 10.2 11.5
Gabbard -0.1 -0.2 -0.4 -0.2 0.1 -0.2
Yang -0.4 -0.5 -0.8 -0.6 -0.4 -0.5
Steyer 1.1 1.0 0.7 0.8 1.0 0.9
Bennet -0.1 -0.2 -0.2 -0.2 -0.3 -0.2
Bloomberg 0.4 0.4 0.3 0.4 0.6 0.4
Patrick 0.1 0.1 0.0 0.0 0.0 0.0

Two candidates—Buttigieg and Klobuchar—strongly outperformed their final New Hampshire Primary WAPA, by an average of 5.8 and 11.5 percentage points (“points”), respectively. The polling momentum they appeared to have coming out of the Iowa Caucuses was apparent in the final results, especially given that the polls conducted in the following week were the least inaccurate.

Sanders narrowly edged Buttigieg, 25.8% to 24.5%, to win the 2020 New Hampshire Democratic Primary, finishing an average 1.2 points higher than his WAPA; again WAPA was more accurate the closer in time it was calculated. Businessman Tom Steyer also finished nearly one point better in the voting (3.6%) than his average WAPA, which differed little in accuracy by time of calculation.

By contrast, Biden (-5.7 points) and Warren (-4.3 points) strongly underperformed their WAPA, with the more recent estimates again the least inaccurate.

One immediate consequence of these results is that three candidates, Colorado Senator Michael Bennet, former Massachusetts Governor Deval Patrick and entrepreneur Andrew Yang, ended their presidential campaigns. As with the 15 former candidates who preceded them, all three men did so with grace and class. One other candidate, United States House of Representatives member from Hawaii Tulsi Gabbard, finished 7th in New Hampshire, barely registered in Iowa and is not close to making any future debates, so her status in this race is somewhat shaky.

Bottom line. To evaluate these comparisons globally, I calculated two difference measures for each of the five WAPA, excluding “DK/Other” (Table 4):

  1. Means of the absolute value of each candidate’s value in Table 3
  2. Sums of the squared differences (“SSE”) between each of the five WAPA value and the results value.

Table 4: Global differences between WAPA and results, 2020 New Hampshire Democratic Primary

Polling period Mean AV Difference SSE
All Polls 3.5 317.4
Since 1st Debate only 3.4 304.2
Since 5th Debate only 2.7 207.7
Since 7th Debate only 2.4 172.4
Since Iowa Caucuses only 2.3 145.3

All five versions of WAPA were quite accurate, despite sharp late movement by Biden, Buttigieg, Klobuchar and Warren, missing by between 2.3 and 3.5 points in either direction, on average. Not surprisingly, the older the collection of polls used to calculate WAPA, the higher the average “miss.”

As with the Iowa Caucuses, meanwhile, and despite newer polls greatly outweighing older polls: the older the set of polls used to calculate New Hampshire Democratic Primary WAPA values, the less predictive they were of the actual results. And, again, the older-polls WAPA may shift too slowly to capture significant late movement.

Given this consistency over the first two contests, I will continue to use this template to assess WAPA.

Now, on to the Nevada Caucuses on February 22, 2020!

Until next time…

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.

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