Final PollyVote forecast: Clinton will win

All numbers are in and, according to the PollyVote, Hillary Clinton will become the first female president of the United States.

Popular and Electoral Vote Prediction

Clinton will win the popular vote by 5.0 percentage points in the two-party vote (52.5% vs. 47.5%). Based on the PollyVote’s historical error, Clinton’s chance to win the popular vote is above 99%. In terms of the Electoral College, Polly predicts Clinton to receive 323 electoral votes compared to 215 for Trump.

Forecast over the course of the campaign

Forecasting is useful only when it can aid decision-making. Thus, Election Eve forecasts are only for entertainment and betting— and writing victory and concession speeches.

The PollyVote has predicted Clinton to win beginning with its first release in early January 2016. Since the first Super Tuesday on March 1st, when it became clear that Trump would become the Republican nominee, Clinton’s lead in the PollyVote forecast averaged 5.6 points. Throughout the course of the campaign, it ranged from a minimum of 3.8 points to a maximum of 8.2 points. In other words, the PollyVote never had Trump close to winning.

Since its launch in 2004, the PollyVote has always correctly predicted the winner on any given day, months in advance, and with little forecast error. Tonight, we will find out whether Polly the Parrot will keep her clean slate. Check back in the days to come as we will provide analyses of the different forecasting methods’ accuracy.

Political scientists predict Clinton will win 334 electoral votes, compared to 204 for Donald Trump

The PollyVote team has conducted the fourth and final round of its state-level expert survey. According to the forecasts of 638 political scientists, Hillary Clinton will win 334 Electoral Votes, compared to 204 for Donald Trump.

This Electoral College prediction thus differs from the results of the previous survey round,  when the experts’ aggregate forecast was that Clinton would gain 358 Electoral Votes, compared to 180 for Trump. The difference is due to Iowa and Ohio, which the experts now see leaning towards the Republicans. For Arizona, the experts predict essentially a pure tossup in both median winning probabilities and vote shares. However, since the average forecast for Clinton’s vote share is slightly above 50%, Arizona is called for the Democrats.

The following map visualizes the experts’ median estimates regarding Clinton’s chance of winning each state.

Nebraska and Maine deserve special attention, since these two states allocate two Electoral Votes to the popular vote winner plus one each to the popular vote winner in each Congressional district. The experts predict that all districts will go with the state-wide popular with two exceptions.

  • In Nebraska’s 2nd district, the Democratic candidate is expected to win 51.0% of the two-party vote.
  • In Maine’s 2nd district, the Republican candidate is expected to win the popular vote with a two-party vote share of 50.6%.

Method

We reached out to political scientists across the country and asked them two short questions:

  1. What share of the vote do you expect the nominees to receive in your home state?
  2. What do you think is Hillary Clinton’s chance of winning the election in your home state?

For experts who regard Nebraska or Maine as their home state, we additionally asked them to predict the outcome in each congressional district.

The survey was conducted from November 6 to 7. A total of 638 experts made estimates as requested. The number of experts by state ranged from 2 to 44. The table below shows the number of respondents per state as well as the median answer for each question.

    Clinton’s predicted
State N Chance of winning Two-party vote
District of Columbia 16 100% 90.4
Hawaii 2 100% 72.3
Vermont 11 99% 67.0
Maryland 22 99% 63.2
Massachusetts 17 99% 66.7
New York 23 99% 63.2
California 21 99% 62.4
Illinois 23 99% 57.9
Connecticut 19 99% 57.9
New Jersey 4 99% 58.5
Washington 7 98% 56.5
Oregon 8 98% 56.8
Delaware 13 98% 62.8
Rhode Island 6 97% 58.8
New Mexico 4 97% 53.0
Minnesota 13 95% 53.2
Maine 8 90% 53.7
Wisconsin 14 89% 52.7
Virginia 44 85% 52.7
Nevada 8 85% 52.4
Michigan 12 83% 51.6
Pennsylvania 19 80% 52.1
Colorado 10 71% 52.0
New Hampshire 10 68% 52.7
Florida 19 55% 50.6
North Carolina 23 55% 51.1
Arizona 13 50% 50.0
Ohio 15 48% 49.5
Iowa 18 43% 48.9
Alaska 4 30% 47.0
Georgia 24 29% 47.6
Missouri 12 25% 47.5
Utah 15 15% 44.4
South Carolina 12 15% 46.3
Kansas 9 15% 43.3
Alabama 6 13% 37.9
Indiana 16 10% 44.2
Texas 22 10% 45.7
Kentucky 5 8% 41.2
Montana 5 5% 41.6
South Dakota 3 5% 42.1
Louisiana 8 5% 43.2
North Dakota 6 4% 36.6
Arkansas 8 3% 41.1
Mississippi 12 2% 42.0
Idaho 15 1% 39.0
Tennessee 5 1% 42.1
West Virginia 9 0% 35.5
Nebraska 5 0% 42.1
Wyoming 4 0% 28.8
Oklahoma 11 0% 30.9

Experts agree: Clinton will win

The PollyVote team has completed its 12th survey of elections experts to forecast the 2016 presidential election. In this survey, conducted between October 29 and 31, 13 academics from a variety of colleges and universities responded.

As in previous rounds, all respondents expect a Clinton win. However, her lead has narrowed substantially compared to the results of the previous survey conducted two weeks ago.

Whereas, in mid-October, the experts expected that Clinton will win the popular vote by more than nine points, the new average forecast is two percentage points lower, at 52.7% of the two-party vote (or about a 5.5-point margin). The individual forecasts ranged from 51.6% to 54.8%, with a standard deviation of only 0.8 points.

Polly thanks the experts who participated in this round, namely

  1. Randall Adkins (University of Nebraska Omaha)
  2. Lonna Rae Atkeson (University of New Mexico)
  3. George Edwards (Texas A&M University)
  4. Keith Gaddie (University of Oklahoma)
  5. John Geer (Vanderbilt University)
  6. Sandy Maisel (Colby College)
  7. Michael Martinez (University of Florida)
  8. Thomas Patterson (Harvard University)
  9. Gerald Pomper (Rutgers University)
  10. David Redlawsk (University of Delaware)
  11. Larry Sabato (University of Virginia)
  12. Michael Tesler (University of California, Irvine)
  13. Charles Walcott (Virginia Tech)

State-wide survey of political scientists: Clinton now at 358 electoral votes

The PollyVote team has conducted the third round of its state-level expert survey. According to the forecasts of 673 political scientists, Hillary Clinton will win 358 Electoral Votes, compared to 180 for Donald Trump.

This Electoral College prediction thus differs from the results of the first and second survey rounds,  when the experts’ aggregate forecast was that Clinton would gain 347 Electoral Votes, compared to 191 for Trump. The difference is due to Arizona (with its 11 Electoral Votes), which the experts now see leaning slightly towards the Democrats.

The following map visualizes the experts’ median estimates regarding Clinton’s chance of winning each state.

Nebraska and Maine deserve special attention, since these two states allocate two Electoral Votes to the popular vote winner plus one each to the popular vote winner in each Congressional district. The experts predict that all districts will go with the state-wide popular with two exceptions.

  • In Nebraska’s 2nd district, the Democratic candidate is expected to win 50.8% of the two-party vote.
  • In Maine’s 2nd district, the Republican candidate is expected to win the popular vote with a two-party vote share of 51.0%.

Method

We reached out to political scientists across the country and asked them two short questions:

  1. What share of the vote do you expect the nominees to receive in your home state?
  2. What do you think is Hillary Clinton’s chance of winning the election in your home state?

For experts who regard Nebraska or Maine as their home state, we additionally asked them to predict the outcome in each congressional district.

The survey was conducted from October 15 to 19. A total of 673 experts made estimates as requested. The number of experts by state ranged from 2 to 39. The table below shows the number of respondents per state as well as the median answer for each question.

Clinton’s predicted
State N Chance of winning Two-party vote
District of Columbia 15 100% 93.8
Vermont 9 100% 67.4
Hawaii 2 100% 76.5
Maryland 26 100% 67.0
New Mexico 5 100% 59.0
Massachusetts 14 100% 67.6
New York 26 99% 65.2
California 23 99% 63.8
Rhode Island 5 99% 61.1
Washington 12 99% 60.3
Illinois 24 99% 59.7
Connecticut 21 99% 62.4
Oregon 9 95% 57.8
New Jersey 5 95% 63.2
Minnesota 18 95% 55.3
Michigan 12 91% 54.3
Delaware 11 90% 63.2
Wisconsin 14 90% 53.9
Virginia 39 90% 56.0
Pennsylvania 20 90% 54.3
Colorado 8 88% 54.9
Maine 14 84% 54.4
New Hampshire 14 80% 54.2
Nevada 5 75% 53.8
Florida 22 73% 51.6
North Carolina 24 65% 51.3
Ohio 12 58% 51.4
Iowa 19 52% 50.5
Arizona 16 50% 50.5
Missouri 11 45% 47.8
Utah 13 40% 47.6
Georgia 26 39% 48.4
Alaska 5 38% 45.8
South Carolina 14 25% 47.0
Indiana 15 20% 46.4
Texas 19 20% 46.7
Kansas 11 15% 46.0
Montana 5 15% 46.2
Kentucky 4 14% 41.5
Arkansas 12 11% 43.2
South Dakota 6 9% 40.3
North Dakota 6 7% 42.0
West Virginia 9 7% 37.6
Mississippi 14 7% 44.7
Alabama 5 5% 38.9
Louisiana 11 5% 40.9
Idaho 14 5% 37.8
Tennessee 8 4% 43.3
Nebraska 4 3% 42.2
Wyoming 4 1% 30.0
Oklahoma 13 0% 37.5

Survey of political scientists: Clinton will win 347 electoral votes

The PollyVote team has conducted the second round of its state-level expert survey. According to the experts’ judgment, Hillary Clinton will win 347 electoral votes, compared to 191 for Donald Trump.

This Electoral College forecast is similar to the previous survey’s results, although Clinton’s lead has considerably narrowed in a number of states, particularly Florida, North Carolina, Iowa, Ohio, and Nevada. That said, even if Clinton lost all five states, she would still end up with 273 electoral votes, three more than necessary to win the election.

The following map visualizes the experts’ median estimates regarding Clinton’s chance of winning each state.

In comparison, the latest PollyVote forecast, which also incorporates the results from the expert survey, predicts Clinton to gain 314 electoral votes, compared to 224 for Trump. This difference results from different forecasts for Ohio and North Carolina. While the experts predict Clinton to prevail in these states, the combined PollyVote forecasts currently favors Trump.

Method

We reached out to political scientists across the country and asked them two short questions:

  1. What share of the vote do you expect the nominees to receive in your home state?
  2. What do you think is Hillary Clinton’s chance of winning the election in your home state?

The survey was conducted from September 19 to 22. A total of 653 experts made estimates as requested. The number of experts by state ranged from 2 to 35. The table at the end of this post shows the number of respondents per state as well as the median answer for each question.

Clinton’s predicted
State N Chance of winning Two-party vote
District of Columbia 13 100% 94.6
Vermont 9 100% 66.7
Hawaii 2 100% 69.9
New York 25 99% 64.2
Massachusetts 20 99% 66.7
Maryland 26 99% 63.6
California 23 99% 62.2
Rhode Island 8 97% 62.7
Washington 11 96% 59.1
Illinois 25 95% 60.4
Delaware 11 95% 60.6
Connecticut 21 95% 60.3
Oregon 11 93% 64.0
New Jersey 5 90% 57.4
New Mexico 4 87% 59.6
Minnesota 17 85% 57.4
Colorado 9 80% 57.8
Wisconsin 14 78% 55.6
Virginia 35 75% 56.0
Pennsylvania 15 75% 56.9
Maine 12 75% 54.8
Michigan 14 70% 54.7
New Hampshire 16 64% 55.1
Florida 16 54% 52.7
North Carolina 22 54% 51.9
Nevada 5 52% 51.2
Ohio 9 51% 52.7
Iowa 15 51% 52.8
Alaska 3 45% 43.4
Arizona 19 40% 48.4
Missouri 11 40% 48.9
Georgia 20 35% 48.6
Arkansas 10 30% 44.2
Indiana 14 18% 48.6
Kansas 8 13% 46.1
Texas 24 13% 44.0
South Carolina 13 10% 45.2
North Dakota 5 10% 43.0
Utah 18 10% 43.6
Kentucky 4 10% 44.4
Wyoming 5 8% 44.0
Alabama 7 5% 40.4
West Virginia 8 5% 37.8
Montana 5 5% 47.7
Mississippi 15 5% 44.1
Louisiana 12 5% 43.2
Tennessee 12 3% 42.1
South Dakota 4 3% 42.2
Nebraska 3 2% 45.5
Idaho 11 1% 34.5
Oklahoma 9 1% 31.7

Political scientists predict Clinton will win 347 electoral votes

Asking experts to predict what is going to happen is probably one of the oldest forecasting methods available. When it comes to predicting election outcomes, we expect experts to have experience in reading and interpreting polls, putting them in historical context, and estimating the likely effects of upcoming campaign events. While the judgment of a single expert should be treated with caution, combining the opinions of several experts improves accuracy.

We have conducted expert surveys as part of the PollyVote project since its launch in 2004. In these surveys, we asked experts to predict the national popular vote. As shown in the chart below, their forecasts have always added valuable information and thus contributed to the accuracy of the PollyVote.  On average, adding expert judgment to the combined PollyVote reduced forecast error by 15%.

For this year’s election, we launched our first survey in December 2015. Since then, the experts’ average forecast always had Clinton in the lead, with a predicted share ranging from 52.2% to 55.5% of the major party vote, which excludes votes for third-party candidates. The latest survey conducted in late July predicted Clinton to gain 52.7%, compared to 47.3% for Trump.

Now, for the first time ever, we set out to conduct a state-level expert survey in order to predict the electoral college. For this, we reached out to political scientists across the country and asked for their help. After respondents revealed their home state, they had to answer two short questions:

  1. What share of the vote do you expect the nominees to receive in your home state?
  2. What do you think is Hillary Clinton’s chance of winning the election in your home state?

A total of 678 experts made estimates as requested. The number of experts by state ranged from one to 42. The table at the end of this post shows the number of respondents per state as well as the median answer for each question. We aim to recruit more experts in states with seven or fewer experts in future survey rounds.

Expert surveys don’t have to include many people to produce accurate forecasts. Prior research shows that eight to twelve experts are close to the optimum. For example, Polly’s survey of the popular vote has provided accurate forecasts with a sample of about twelve experts.

The map below shows Clinton’s chance of winning per state. This expert survey predicts that Hillary Clinton will win 347 electoral votes, compared to 191 for Donald Trump. This forecast is in line with those from Daily Kos, NYT Upshot, PredictWise, Sabato, and the combined PollyVote.

Experts’ Electoral College forecast

Overview of results

Clinton’s predicted
State N Chance of winning Two-party vote
District of Columbia 18 100% 94.6
Vermont 11 99% 66.7
New York 24 99% 64.2
Massachusetts 11 99% 66.7
Maryland 26 99% 63.6
California 24 99% 62.2
Illinois 27 98% 60.4
Washington 11 97% 59.1
Rhode Island 8 97% 62.7
Minnesota 16 95% 57.4
Delaware 7 95% 60.6
Connecticut 22 95% 60.3
New Jersey 4 93% 57.4
Wisconsin 14 90% 55.6
Oregon 11 90% 64.0
New Mexico 6 90% 59.6
Virginia 42 87% 56.0
Colorado 10 86% 57.8
Michigan 8 85% 54.7
Pennsylvania 18 84% 56.9
Maine 16 83% 54.8
New Hampshire 11 80% 55.1
Ohio 9 75% 52.7
Hawaii 1 75% 69.9
Florida 21 75% 52.7
North Carolina 22 63% 51.9
Nevada 1 57% 51.2
Iowa 23 57% 52.8
Georgia 34 45% 48.6
Arizona 21 43% 48.4
Missouri 9 40% 48.9
Indiana 15 40% 48.6
Wyoming 2 30% 44.0
Kansas 11 30% 46.1
South Carolina 15 25% 45.2
North Dakota 3 25% 43.0
Utah 12 23% 43.6
Arkansas 15 20% 44.2
Alabama 6 18% 40.4
West Virginia 8 15% 37.8
Nebraska 10 15% 45.5
Montana 7 15% 47.7
Kentucky 7 15% 44.4
Texas 21 10% 44.0
Tennessee 11 10% 42.1
Mississippi 8 10% 44.1
Louisiana 12 8% 43.2
South Dakota 3 5% 42.2
Oklahoma 12 4% 31.7
Idaho 11 3% 34.5
Alaska 3 0% 43.4