Quinnipiac University and Emerson College: Mirror-image pollsters?

In three earlier posts—most recently here—I analyzed all polls conducted by Emerson College (“Emerson”) of 2020 presidential, senatorial and gubernatorial elections. I found that they had a clear bias towards the Republican candidate, on average, compared to all other polls of the same election.

As I continue to analyze polls of the presidential election between former Vice President Joseph R. Biden, Jr. and President Donald J. Trump, as well as this year’s 35 Senate and 11 gubernatorial elections, I have observed the opposite mathematical bias for Quinnipiac University (“Quinnipiac”) polls.

In fact, as we will see, the two polling organizations nearly mirror each other in their mathematical bias.


Let us begin with the national race between Democrat Biden and Republican Trump. Using all 632 publicly-available polls released since January 1, 2019, I calculated a weighted-adjusted polling average (WAPA) of 8.3. That is, adjusting for time (with polls conducted after August 29 weighted and additional 1.5 times higher and polls conducted since September 29 3.0 times higher), pollster quality and partisan lean, Biden leads Trump by a little over eight points nationally. Emerson has an A- rating, and a historic lean of 0.3 points Democratic, while Quinnipiac has a B+ rating, and a historic lean of 0.2 points Democratic.

Table 1: State-level 2020 presidential election polling averages by Emerson College and Quinnipiac University compared to all other pollsters in the same state

StateQuinnipiac  Emerson 
California   29.328.60.8
Iowa   -0.40.5-0.9
Massachusetts   36.934.32.6
Montana   -12.1-6.1-5.9
Nevada   -0.16.0-6.1
New Hampshire   7.88.1-0.3
North Carolina   0.92.1-1.2
South Carolina-4.2-7.12.8   
AVERAGE All States3.5  -0.5
AVERAGE Ohio, Pennsylvania, Texas1.9  -0.7

However, using the same calculation method—except for ignoring partisan lean—the 20 Emerson polls conducted by Emerson give Biden “only” a 3.7-point lead, which is 5.3 points more Republican than the average of the other 612 polls. At the same time, the 13 Quinnipiac polls give Biden a 9.9-point lead, which is 1.0 points more Democratic than the average of the other 619 polls. Put another way, Quinnipiac polls “see” a race that is 6.3 points more favorable to Biden than Emerson polls do, though both give Biden a solid lead.

While national polls are interesting—and plentiful—it is the Electoral College that determines who wins presidential elections. Table 1 compares state-level presidential polling averages by Emerson and Quinnipiac, in states where they have assessed the presidential election at least twice, to those calculated by all other pollsters in the state; positive values indicate a Democratic lead or pro-Democratic bias, and negative values indicate the opposite. Emerson has conducted one poll of the presidential election in Florida, Georgia, New Mexico, New Jersey and South Carolina; Quinnipiac has conducted one poll of the presidential election in Colorado, Connecticut, Iowa, Michigan, New Jersey, New York and Wisconsin.

In the 13 states where Emerson has assessed the 2020 presidential election, the average bias is only 0.5 points towards Trump, fully 4.8 points lower than its national bias toward Trump. By contrast, in the eight states where Quinnipiac has assessed this election—five of them in the south, the average bias is 3.5 points toward Biden, 2.5 points higher than its national bias toward Biden. The gap between the two polling organizations also narrows from 6.3 to 4.0 points at the state level.

Notably, while Quinnipiac has an average bias toward Biden in all eight states—ranging from more than five points in Georgia, Maine and Florida to around one point in Ohio and Texas—Emerson’s bias is evenly split across its 13 multiple-assessment states, ranging from nearly six points towards Trump in the western states of Montana and Nevada to between two and four points toward Biden in the disparate states of Arizona, Massachusetts (where Emerson College is located) and Michigan.

Curiously, Emerson and Quinnipiac have both assessed the 2020 presidential election in only three states—Ohio, Pennsylvania and Texas—multiple times since January 1, 2019. In these three states, the bias is relatively narrow: Trump +0.7 for Emerson and Biden +1.9 for Quinnipiac, for a gap of “only” 2.6 points.


Turning to other statewide elections in 2020, Table 2 compares Senate election polling averages by Emerson and Quinnipiac, in states where they have conducted such polls at least twice since January 1, 2020, to those calculated by all other pollsters in the state. Emerson has conducted one Senate election poll in Georgia, assessing both seats on the ballot this year, as well as in Arizona, Iowa, Michigan, Minnesota, New Hampshire and New Jersey; Quinnipiac has conducted one Senate election poll in Iowa and Michigan. For the “jungle primary” in which Georgia Republican Senator Kelly Loeffler seeks reelection, I analyze the difference between the total percentage for all Democratic candidates and the total percentage for all Republican candidates.

Table 2: 2020 Senate and gubernatorial election polling averages by Emerson College and Quinnipiac University compared to all other pollsters in the same election

StateQuinnipiac  Emerson  
Montana   -8.4-0.8-7.6
North Carolina   2.65.1-2.4
South Carolina0.0-2.82.8   
AVERAGE  3.3  -5.0

In a reverse of state-level presidential election polling, Quinnipiac has assessed six Senate elections multiple times—again focusing on the south, while Emerson has only assessed Senate elections in Montana and North Carolina more than once; no Senate election has been polled multiple times by both pollsters. Quinnipiac has an average 3.3-point bias toward Democratic Senate nominees, nearly identical to its 3.5-point state-level presidential election bias. By contrast, albeit only in two Republican-leaning states, Emerson has an average 5.0-point bias toward the Republican Senate nominees, nearly identical to their Trump bias nationally, and fully 4.5 points higher than their state-level bias toward Trump. Overall, and recognizing this is not an apples-to-apples comparison, Quinnipiac Senate election polls lean 8.3 points more Democratic than Emerson Senate election polls.

Quinnipiac has been especially Democratic-leaning in Georgia’s two Senate elections, with average pro-Democratic-nominee biases of 6.2 and 7.2 points, and in Maine, while they have shown minimal bias in Kentucky and Texas. As with the presidential election, meanwhile, Emerson has a whopping 7.6-point bias toward incumbent Montana Republican Senator Steve Daines in his race against Democratic Governor Steve Bullock; they are relatively closer to the mark in North Carolina, where Democrat Cal Cunningham has a small lead against incumbent Republican Thom Tillis.

Quinnipiac has conducted no gubernatorial election polls this year, while Emerson has conducted one poll in New Hampshire and multiple polls in Montana (6.5 points more Republican) and North Carolina (7.4 points more Republican), with a large average pro-Republican bias of 6.9 points!


Table 3 lists the average partisan biases for Emerson and Quinnipiac for each set of races.

Table 3: Average partisan biases in Emerson College and Quinnipiac University polls across multiple election categories


While Quinnipiac has had only a relatively small pro-Biden bias in national polls, they have had an overall lean of 2.6 points Democratic across all elections they have assessed multiple times. By contrast, while Emerson has been very close to the all-polls average in their state-level presidential election polling, they have had an overall lean of 4.4 points Republican across all elections they have assessed multiple times. Overall, Quinnipiac has leaned fully 7.0 points more Democratic than Emerson has.

I will not attempt to “explain” these relative partisan biases, though they almost certainly result from some combination of how the demographic distribution of the likely 2020 electorate is modeled, the fact Quinnipiac shifted to “likely voters” models more recently than Emerson did, how hard they “push” initially undecided voters to choose one candidate, and the relative partisan leanings of demographic categories within their respective samples.

I will say, though, that the final Democratic-minus-Republican margin will almost certainly be very close to the midpoint of the two polling averages plus one point Democratic—at least in elections assessed at least once by Emerson and by Quinnipiac.

Until next time…please stay safe and healthy…and if you have not already voted, please do so as soon as you can!

October 2020 update: Democratic control of the Senate looks increasingly likely

Democrats are poised to do extremely well when voting concludes on November 3, 2020—just 16 days from now; as I write this, more than 26.5 million votes have already been cast, which is 19% of the total 2016 turnout. They are a near-lock to continue to have a majority of members of the United States House of Representatives (“House”), and their presidential nominee, former Vice President Joseph R. Biden, Jr., is the clear favorite to win.

And then there is the United States Senate (“Senate”). Currently, there are 53 Republicans, 45 Democrats and 2 Independents who caucus with Democrats in the Senate. To regain control, Democrats must either win a net total of four Senate seats OR a net total of three Senate seats while winning back the presidency; as president of the Senate, Vice President Kamala Harris would break the 50-50 tie.

As of now, Democrats are favored to regain control of the Senate. This conclusion is based upon a political climate strongly favoring Democrats—they lead by 7.2 percentage points on the generic ballot[1]—and all publicly-available polls conducted since January 1, 2020.

Before continuing, here is the October 2020 lighthouse photograph in my Down East 2020 Maine Lighthouses wall calendar.


In a previous post, I detail how I calculate and combine…

  1. “Expected Vote” (how a generic Democrat would fare against a generic Republican given state partisan lean, incumbency and partisan climate) and
  2. My weighted-adjusted polling averages (“WAPA”), which average two versions of WAPA: one treating all polls from the same pollster as statistically independent and one calculating a time-weighted average for each pollster

…into a single projected Democratic-minus-Republican margin and the probability the Democrat wins. As of now, the latter accounts for at least 89% of the projected margin in the Senate races assessed with a publicly-available poll at least once in 2020; in the six states with no polling,[2] the Expected Value is the projected margin.

Table 1 reports two projected Democratic-minus-Republican margins and Democratic win percentages for this year’s 35 Senate elections: one using all polls conducted since January 1, 2020, and one using only polls conducted since the two national party conventions. I now weight all polls conducted after August 28 (the day the conventions ended) and before September 29 (the day of the first presidential debate) 1.5 times higher than previous polls, and I weight all polls conducted entirely after September 29 3.0 times higher. The table is sorted by likelihood the Democrat (or Independent Al Gross in Alaska) wins the election, based upon all 2020 polls.

Table 1: Projected 2020 Democratic minus Republican margins and likelihood of Democrat winning calculated two ways

StateCurrent PartyMargin since 1/1/2020Dem win%Margin since 8/29/2020Dem win %
Rhode IslandDEM29.4100.0%29.4100.0%
New JerseyDEM23.9100.0%24.3100.0%
New MexicoDEM10.799.8%9.999.7%
New HampshireDEM14.499.8%14.199.8%
North CarolinaGOP5.094.1%4.893.5%
South CarolinaGOP-3.116.9%-2.324.4%
South DakotaGOP-21.20.1%-21.20.1%
West VirginiaGOP-20.60.0%-20.60.0%

Georgia Republican Senator Kelly Loeffler, appointed by Governor Brian Kemp in December 2019 after Senator Johnny Isakson retired, is running for reelection in a “jungle” primary in which every candidate, regardless of party affiliation, appears on the November 3 ballot. If no candidate tops 50%, a runoff election between the top two vote-getters will take place on January 5, 2021. Republican House Member Doug Collins of Georgia is also running, as are Democrats Raphael Warnock, senior pastor of Ebenezer Baptist Church in Atlanta, Matt Lieberman, son of 2000 Democratic vice-presidential nominee Joe Lieberman, and former United States Attorney Ed Tarver. I calculate WAPA both for the all-candidate election on November 3—polls of which strongly imply either a Warnock-Loeffler or Warnock-Collins runoff—and hypothetical head-to-head matchups between the top two Republicans and the top three Democrats, combining them into a single “Democrat vs Republican” average as follows:

  1. Calculate averages, weighted by number of publicly-available 2020 polls, of the Democratic margins over Loeffler and Collins. Based on 11 total polls, Loeffler is about 3.6 points behind the top three Democrats, while Collins is behind 1.5 points based on nine total polls.
  2. Take the unweighted average of the Loeffler and Collins averages
  3. Calculate a final average “Democratic vs. Republican” margin, giving the head-to-head matchups twice the weight of the “all candidates” WAPA


Let us examine these 35 elections in groups.

Safe Democratic (10). Senators Edward Markey of Massachusetts, Jack Reed of Rhode Island, Richard Durbin of Illinois, Cory Booker of New Jersey, Chris Coons of Delaware, Jeff Merkley of Oregon, Mark Warner of Virginia and Jeanne Shaheen of New Hampshire should easily win reelection by double-digit margins, while in New Mexico’s open seat House Member Ben Ray Lujan is expected to beat meteorologist Mark Ronchetti by around 11 points. First-term Senator Tina Smith of Minnesota is now a clear favorite as well, with a final margin around nine points.

Likely Democratic (1). First-term Senators Gary Peters of Michigan is considered vulnerable because he represents the closest state in the 2016 presidential election. And when examining only the “polls are statistically independent” WAPA, Peters’ margin has dropped sharply from 9.6 points through the end of the conventions to 5.5 points since then. Nonetheless, I expect him to prevail over businessman John James by low-to-mid-single-digits.

Likely Democratic flips (4). Four incumbent Republican Senators—Cory Gardner of Colorado, Martha McSally of Arizona, Susan Collins of Maine and Thom Tillis of North Carolina—appear headed for defeat by single-digit margins; these margins changed little pre- and post-conventions, with McSally gaining 0.9 points and Collins losing 1.6 points. McSally and Gardner are the most likely to lose—by high single digits—to, respectively, former Governor John Hickenlooper and former astronaut Mark Kelly, husband of former Arizona House Member Gabrielle Giffords, who was shot and severely wounded in January 2011. Collins and Tillis, meanwhile, trail Maine Speaker of the House Sara Gideon and former North Carolina State Senator Cal Cunningham, respectively, by around five points.

Lean Democratic flip (1). Based solely on expectations—incumbent Republican in a lean-Republican state running for reelection in a strong Democratic year—Senator Joni Ernst of Iowa entered this election season no better than even money to win reelection. And now she trails businesswoman Theresa Greenfield by just under three points, with Greenfield’s margin increasing by 1.6 points after the conventions. This is enough to make Ernst a modest underdog—and this debate flub is likely to hurt Ernst even more.

Toss up (1). The Georgia special election is extremely difficult to assess, as I wrote earlier. Depending on which set of polls (all, or only post-conventions) we examine, the Democrat is either a one-point underdog or a three-point favorite—and that assumes a Democrat, as now seems very likely, makes the January run-off election. Given the extreme uncertainty surrounding this election, I consider it a toss-up.

Likely Republican flip (1). While Alabama Senator Doug Jones is outpacing his fundamentals—running as a Democratic incumbent after only three years in a very Republican state—by 9.6 points, he will almost certainly lose to former college football head coach Tommy Tuberville. In fact, losing “only” by mid-single-digits would be a moral victory for Jones.

Lean/likely Republican (4). There are four Republican-held Senate seats—in states averaging 16.8 points more Republican than the nation as a whole—which Democrats have between a 17% and 28% chance of winning, using all polls conducted since January 1, 2020; Democrats trail in these elections by an average 2.5 points. The outlook improves slightly when only post-convention polls are examined, with the average deficit dropping to 2.2 points.

Going from least to most likely to flip:

–In South Carolina, former state Democratic Party Chair Jaime Harrison has closed the gap with Senator Lindsey Graham from 4.0 points pre-conventions to 2.0 post-conventions, but still has only about a one-in-four chance of winning. Notably, a Harrison victory would give South Carolina two male African-American Senators, the other being Republican Tim Scott.

–In Montana, Democratic Governor Steve Bullock has lost ground recently to Senator Steve Daines, watching his deficit increase from 1.8 points to 2.7 points post-conventions, while his likelihood of prevailing has dropped from 26.3% to 17.5%.

–In the regularly-scheduled Georgia Senate election, journalist Jon Ossoff continues to narrow the gap with Senator David Perdue, who continues to perform in racist and anti-Semitic ways, climbing from 2.6 points to 1.5 points down after the conventions. I estimate Ossoff now has a roughly 30% chance of winning, up slightly from 25%.

–In the open seat in Kansas, which has not elected a Democrat to the Senate since 1932, State Senator (and former Republican) Barbara Bollier is mounting a surprisingly strong challenge to House Member Roger Marshall. Prior to the conventions, she had already narrowed the “expected” deficit from 16.2 points to 3.6 points. Since the conventions, she trails by only 0.7 points, giving her a 38% chance to win.

Assuming the outcomes in these four races are unrelated to each other—a poor assumption, to be sure—Democrats have a 70% chance of winning at least one of these races, with Georgia and Kansas being the most likely.

Likely Republican (3). Democrats—and one Independent—are at least making life uncomfortable for three Republican Senators seeking reelection: Dan Sullivan of Alaska, Cindy Hyde-Smith of Mississippi, and John Cornyn (Senate Majority Whip) of Texas. Orthopedic surgeon Gross has closed the gap against Sullivan from 6.0 to 3.7 points, though that still gives him only a 1-in-9 chance of winning. First-term Senator Hyde-Smith again faces former Agriculture Secretary Mike Espy, who lost by “only” 7.2 points in 2018. Through August, Espy trailed by double digits, but a poll by the partisan-netural Tyson Group in late August had him trailing just 40-41 (with an astonishing 19% undecided or choosing a different candidate), which narrowed the deficit to around 8.7 points overall. The previous Tyson Group poll, conducted in March, had Espy trailing by 26 points! Finally, United States Air Force veteran Mary Jennings “M. J.” Hegar continues to chip away at Cornyn’s lead, climbing from 7.8 points to 5.8 points down. All this being said, I still expect Sullivan, Hyde-Smith and Cornyn to win with low-to-mid-single-digit margins.

Safe Republicans (10). Senators Bill Cassidy of Louisiana, Ben Sasse of Nebraska, Mike Rounds of South Dakota, Tom Cotton of Arkansas, James Risch of Idaho, Shelley Moore Capito of West Virginia and James Inhofe of Oklahoma should easily win reelection by double-digit margins. And in Tennessee and Wyoming, respectively, former United States Ambassador to Japan Bill Hagerty and former House Member Cynthia Lummis are expected to win by similar margins. Finally, while former United States Marine fighter pilot Amy McGrath has run a spirited race in Kentucky against Republican Senate Majority Leader Mitch McConnell, she is still likely to lose by around 10 points.

In sum, Democrats appear all but certain to net at least one Senate seat, losing in Alabama while winning in Arizona and Colorado, and are very well-positioned to win seats in Maine, North Carolina and, with less certainty, Iowa, giving them a narrow 51-49 majority; Warnock defeating Collins or Loeffler in January would increase that lead to 52-48. The question then becomes whether Democrats can add further seats in Georgia, Kansas, Montana or South Carolina…and even pull off an upset or two in Alaska, Mississippi or Texas.

Here is another way to think about these races.

An old “rule of thumb” says an incumbent polling below 50% is likely to lose, because undecided voters—who presumably know a great deal about the incumbent—will break against her/him. In reality, undecided voters tend to break in unpredictable ways, albeit generally in the same partisan direction in so-called “wave” years. Given the tens of millions of votes which will already have been cast by November 3, which then get factored into polling, this year’s undecided voters are even harder to predict—and may even break strongly in favor of Republicans, simply by virtue of not having voted early.

Table 2 lists candidate post-convention polling averages, prior to adjustment for partisan pollster bias, in the 15 most competitive Senate races, sorted by Democratic percentage:

Table 2: Post-conventions polling averages for Democratic and Republican 2020 Senate candidates

North CarolinaYes46.8%41.4%
South CarolinaYes44.8%46.2%
Georgia–LoefflerYes41.9% total44.6% total
MississippiYes41.0% in 2 Aug polls44.0% in 2 Aug polls

Kelly and Hickenlooper in Arizona and Colorado, respectively, are already at or above 50%, as is Tuberville in Alabama, suggesting these races are all but over. Incumbents Collins and Tillis, in Maine and North Carolina, respectively, are struggling to crack 42%, while Ernst in Iowa and Loeffler/Collins are well below 45%. For that matter, Marshall is struggling to reach 44% in Kansas, which leans 23.4 points Republican! With just over two weeks left, it is hard to see these incumbents make up that ground with voters, even if none of their Democratic opponents are polling much higher than 47%. Mississippi, meanwhile, is very difficult to gauge: in five polls taken between January and May, Hyde-Smith leads by an unweighted 52-36, but in the two August polls that deficit drops sharply to 44-41. This truly is the sleeper race.

Four other Republican incumbents are hovering around 46%–Graham, Perdue, Sullivan and Cornyn—which is in a kind of gray area between safe and in serious trouble. The good news for the latter two is that their opponents are struggling to top 42%. The bad news for Graham and Perdue is that their opponents are hovering around 45%–making undecided voters truly decisive in these two elections.

Peters in Michigan and Smith in Minnesota are hovering just below 48%, meanwhile, though they are still well ahead of their Republican opponents, who average around 40%. Daines in Montana, finally, is at 48.5%, close enough to 50% that Bullock may have a hard time catching him.

Bottom line: Democrats currently appear poised to pick up at least four seats, giving them a 51-49 majority. They are at least even money to win the Georgia special election and have at least modest opportunities to flip one or more of seven other Republican-held seats. If I simply sum the probabilities Democrats win each race, I get +5.1 using all polls and +6.0 using only post-conventions polls, though this is very “back of the envelope” methodology. Still, while Democrats could still net only one or two seats, a net gain of three-six seats is by far the likeliest outcome.

The strong likelihood of Democrats regaining control of the Senate is boosted by two historically-plausible scenarios:

  1. All polls are overestimating Democratic margins by 3.0 points.

In this scenario, Democrats remain strongly favored in Arizona (90.8%) and Colorado (97.3%) while headed for certain defeat in Alabama (0.0%), and they would be favored in Maine (74.0%) and North Carolina (75.5%), with Iowa essentially a toss-up (44.2%). Michigan would begin to get dicey as well, though Peters would still be an 89.0% favorite. Democrats would not be favored by more than 10% (Georgia special election) in any other race, though they would probably just net the three seats they need to regain control. The “back of the envelope” estimate is Democrats winning 2.9 seats, making control toss-up/Lean Democrat.

  • All polls are underestimating Democratic margins by 3.0 points.

While Alabama is still a near-lock to flip Republican, Democrats would be at least a 95.6% favorite to win Arizona, Colorado, Iowa, Maine and North Carolina for a minimum net gain of four seats. Democrats would also be 3-1 favorites in the Georgia special election, and the Senate races in South Carolina (51.0%), Georgia (61.9%), Montana (63.0%) and Kansas (64.7%) would be toss-ups, with Democrats likely to win at least two of them. They would also have a 35.2% chance of winning Alaska, and even a 13.6% chance of winning Texas. The “back of the envelope” estimate is Democrats netting 7.6 seats, making control a near-certainty, with a net 9-11 seats plausible, if still unlikely.


Very little has changed in the 11 states holding gubernatorial elections in 2020. Regardless of which polls you examine or what over- or under-estimation assumptions you make, Republicans are heavily favored to hold governor’s mansions in Vermont, New Hampshire, Indiana, Missouri, West Virginia, North Dakota and Utah. The closest margin is Missouri, where State Auditor Nicole Galloway trails Governor Mike Parson by an estimated 8.3 points. Similarly, Democrats are heavily favored to retain governor’s mansions in Delaware, Washington and North Carolina by double-digit margins, while Republican House Member Greg Gianforte is very likely to win back the Montana governor’s mansion—he leads Democratic Lieutenant Governor Mike Cooney by an estimated 7.4 points—for the first time in 16 years. Thus, Republicans will almost certainly net one governor’s mansion this year, increasing their edge to 27-23.

Until next time…please stay safe and healthy…

[1] That is, some variant of “If the election for United States House of Representatives was held today, would you vote for the Democrat or the Republican in your Congressional district?”

[2] Rhode Island, Illinois, Tennessee, Nebraska, South Dakota, Wyoming

Biden is now the clear favorite to win the 2020 presidential election

On November 3, 2020, a weeks-long presidential election between incumbent Republican Donald J. Trump and his Democratic challenger, former Vice President Joseph R. Biden, Jr., will end. As I write this, more than 23 million Americans—including yours truly—have already cast their ballots. This number is just over 1/6 of total votes cast in 2016.

Following an extremely contentious first presidential debate on September 29, and dueling town hall events on October 15, here is an updated assessment of the 2020 presidential election; you may find my previous assessment here. Assessments are based upon all publicly-available polls of the presidential election—nationally and by state, recognizing presidential elections are determined by the Electoral College—conducted since January 1, 2019.

A total of 606 national polls assessing Biden vs. Trump have been conducted since January 1, 2019,[1] of which:

  • 499 have been conducted since January 1, 2020
  • 140 have been conducted entirely since the end of the national party conventions on August 28
  • 44 have been conducted entirely since the first presidential debate

The 70+ pollsters who have assessed this election at least once have an average B- FiveThirtyEight pollster rating, as do the 50+ pollsters who have assessed the election multiple times.

Figure 1 shows how Biden has fared monthly against Trump in 2020, using my weighted-adjusted polling averages (WAPA). I use pollster rating data to adjust for partisan lean (historic tendency to err more Democratic or Republican than other pollsters in analogous races) and quality.[2] I weight more recent polls higher, using the number of days since January 1, 2019 divided by 673, the number of days between January 1, 2019 and November 3, 2020. I then average two versions of WAPA: one treating polls by the same pollster as statistically independent, and one treating all polls by the same pollster as a single, time-weighted value; differences between estimates are usually negligible. Polls conducted after August 28, but before September 30, are weighted 1.5 times higher than prior polls, and polls conducted entirely after September 29 are weighted 3.0 times higher.

Figure 1

Using all polls conducted since January 1, 2019, Biden leads Trump nationally by 8.2 percentage points (“points”), with his lead rising to 8.8 points only using polls conducted since the conventions, and to 9.9 points only using the 46 polls with an October 2020 field date midpoint. Biden’s margin over Trump has risen from just over four percentage points in January and February, when he was fighting for the 2020 Democratic presidential nomination, to just under six points in the three months after Biden’s decisive win in the 2020 South Carolina Democratic presidential primary, to between seven and 10 points since June 1, the day protesters were forcibly cleared from Lafayette Square so Trump could pose in front of St. John’s Episcopal Church holding a copy of the Bible.


Again, though, presidential elections are fought across 50 states and the District of Columbia (“DC”), with the plurality winner in each state/DC winning every electoral vote (“EV”) from that state. Now that SurveyMonkey—a D- pollster with a 5.0-point historic Democratic bias—has released a set of polls covering June, July, August and September, every state/DC has now been polled at least four times.

Table 1 reports two projected Democratic-minus-Republican margins and corresponding EV win percentage (“EV%”) for every state and DC: one using all polls conducted since January 1, 2019, and one using only polls conducted since the two national party conventions. The table is sorted from highest to lowest EV% using the larger set of polls. For margin and EV% calculations, see here.

Table 1: Projected 2020 Biden-Trump margins and likelihood of winning EV calculated two ways

StateMargin since 1/1/2019EV%Margin since 8/29/2020EV%
New York27.1100.0%31.4100.0%
Rhode Island16.8100.0%23.4100.0%
New Jersey19.3100.0%19.5100.0%
New Mexico11.899.9%12.999.9%
New Hampshire7.899.0%8.999.4%
North Carolina1.871.7%1.973.4%
South Carolina-7.70.9%-7.61.0%
South Dakota-22.10.0%-19.50.0%
North Dakota-23.30.0%-21.30.0%
West Virginia-21.50.0%-16.70.0%

With just 17 days until Election Day 2020, Joe Biden is the clear favorite to be elected the 46th president of the United States. The most direct way for Biden to win the Electoral College is to win the 232 EV from the states won by Democratic presidential nominee Hillary Clinton won in 2016, then add Michigan (98.9%), Wisconsin (96.8-98.2%) and Pennsylvania (96.1-96.7%); he could even lose Nevada (92.0-96.2%) and still win 273 EV, three more than necessary. Taking the product of the likelihood of victory for the states totaling 273 EV yields a minimum 89.5% probability Biden wins the Electoral College using all polls, which rises to 91.8% using only post-convention polls. These are very rough probabilities given how correlated voting behavior is across demographically-similar states, though they are broadly in line with other public estimates.


  • He is at least a 92.0% favorite in enough states—and by margins of at least 4.5 points—to earn him 278 or 279 EV, depending on what happens in Maine, which, along with Nebraska, allocates two EV to the statewide winner and one each to the winner of its Congressional districts. At this point, Biden would already have won the presidency.
  • He is favored better than 4-1 to win the 11 EV of Arizona and the 29 EV of Florida, by around three points each, increasing Biden’s total to 318 or 319 EV.
  • He is favored 5-2 to win North Carolina, by a hair under two points, for an additional 15 EV, increasing Biden’s total to 333 or 334 EV.
  • The 40 combined EV of Ohio, Georgia and Iowa are essentially toss-ups, with projected margins of less than one point, increasing Biden’s total to between 339 and 375 EV; Biden has a roughly 81% chance of winning at least one of them. That said, winning Iowa would require a winning a solid majority of undecided voters, Ohio has been trending slightly away from Biden, and Georgia is literally 50-50.

Plus, it might take only a sharp break by undecided voters and a modest polling error for Biden to win the ultimate prize—Texas (-2.1). Thus, while something in the mid-300’s currently appears the most likely EV total for Biden, 413 (or more) EV cannot be discounted.

Using the simplistic—perhaps even simple-minded—method of multiplying Biden’s probability of winning each state by its EV, then summing, yields a “projected” EV total of just under 350 EV using both sets of polls, essentially adding Michigan, Pennsylvania, Wisconsin, Florida, Arizona, North Carolina, and one of Ohio/Georgia/Iowa to the states Clinton won.

Biden’s lead looks even stronger after making either of two historically-valid assumptions; calculation use all polls conducted since January 1, 2019:

Polls systematically overestimate Biden’s margins by 3.0 points.

In this scenario, Biden’s projected EV drops to 300.8, 28.8 more than required, with a minimum “path of least resistance” probability of 51.0%. He would be favored at least 78.8% to win in enough states to win 273 EV. Thus, even if Biden “only” wins the national popular vote by 5.2 points, he would likely still prevail, though the decisive states of Wisconsin and Pennsylvania would be decided by relatively narrow margins, with all votes possibly not counted for a week or more. That Biden could win the national popular vote by more than five points, yet still only be a modest favorite to win at least 270 EV, demonstrates the recent Republican advantage in the Electoral College.

Polls systematically underestimate Biden’s margins by 3.0 points.

In this scenario, Biden’s projected EV are a landslide-level 390.3, 120.3 more than necessary, with a minimum “path of least resistance” probability of 97.2%.  He would be favored at least 80% to win enough states to earn 368 EV, while being a 3-1 favorite in Iowa, for a total of 374 EV. Biden would even be a slight favorite (61.7%) in Texas, which he would be projected to win by 0.8 points. Biden would also have a 20.4% chance of winning Alaska’s 3 EV and a 10.4% chance of winning Missouri’s 10 EV. The last presidential candidate to come close to 426 EV was Republican George H. W. Bush, who won 426 EV in 1988.


None of this is to say Biden is guaranteed to be elected the next president of the United States. Even with the massive surge in early voting, delays in mail delivery—allegedly orchestrated by the Postmaster General—could leave millions of votes uncounted because they did not arrive by November 3. Pennsylvania, the most likely “tipping point” state—the one giving either Biden or Trump the necessary 270 EV when states are ordered most to least Democratic—is already showing the strain of trying to establish absentee voting on the fly. Moreover, while Biden’s national polling lead has ranged between seven and 10 points since June 1, a last-minute “October surprise” could erase this lead, though this “e-mails” story is unlikely to be it.

Nonetheless, unlike Clinton in 2016, Biden has a sufficiently-wide range of paths to 270 EV that I estimate he is at least a 92% favorite to be elected president of the United States on November 3, 2020—or whenever ballots are ultimately counted.

Until next time…please stay safe and healthy…

[1] I limit iterations of tracking polls only to those with non-overlapping field dates.

[2] I halve the number value assigned to a letter grade for any poll conducted since June 1, 2020 which samples adults instead of registered or likely voters.