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

Clinton leads by more than 5 points in new expert survey

The Pollyvote team has completed its 8th survey of elections experts to forecast the 2016 presidential election. In the late July survey, conducted between July 29 and 31, 12 academics from a variety of colleges and universities responded.

All but one responding experts expected a Democratic win. The average forecast is that Democratic nominee Hillary Clinton will receive 52.7% of the two-party vote, with individual forecasts ranging from 48.5% to 55.4%. The expert forecast is thus 1.5 percentage points lower than in the previous survey, when the mean forecast was that Clinton will receive 54.2%.

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. John Coleman (University of Minnesota)
  4. George Edwards (Texas A&M University)
  5. Sandy Maisel (Colby College)
  6. Michael Martinez (University of Florida)
  7. Thomas Patterson (Harvard University)
  8. Gerald Pomper (Rutgers University)
  9. David Redlawsk (Rutgers University)
  10. Larry Sabato (University of Virginia)
  11. Michael Tesler (University of California, Irvine)
  12. Charles Walcott (Virginia Tech)

New high for Democrats in PollyVote expert survey

The Pollyvote team has completed its seventh survey of elections experts to forecast the 2016 presidential election. In the late June survey, conducted between June 28 and 30, 12 academics from a variety of colleges and universities responded.

All responding experts expected a Democratic win, with forecasts of the popular vote ranging from a minimum of 52.0% to a maximum of 57.0%. The mean forecast is that the Democrats will garner 54.2% of the major-party vote (compared to 45.8% for the Republicans).

The predicted Democratic vote share is thus 1.8 percentage points higher than in the previous survey, conducted in late May, when the mean expert experts had predicted a vote share of 52.4%. The current results also show the highest vote share for the Democrats in all expert surveys conducted since January.

Polly thanks the experts who participated in this round, namely

and one expert who preferred to remain anonymous.

Experts see Democrats’ lead narrowing to 5 points

The Pollyvote team has completed its sixth survey of elections experts to forecast the 2016 presidential election. In the late May survey, conducted between May 29 and 31, 13 academics from a variety of colleges and universities responded.

All but one responding experts expected a Democratic win. The average expert forecast for the Democratic share of the two-party vote was 52.4%, compared to 47.6% for the Republicans.

The predicted Democratic vote share is thus 0.8 percentage points lower than in the previous survey, conducted in late April, when the mean expert experts had predicted a vote share of 53.2%.

Polly thanks the experts who participated in this round, namely

and one expert who preferred to remain anonymous.

New citizen forecast predicts tight race: Clinton 50.5% vs Trump 49.5%

A new ABC News/Washington Post poll provided updated citizen forecasts. In the polls, people were asked: “Regardless of whom you support, if Clinton and Trump are the nominees for president, who would you expect to win: Clinton or Trump?” According to the results, 50% of respondents expected Clinton to win, whereas 40% predicted a Trump victory. Translating these results into two-party vote-shares yield a forecast of 50.5% for Clinton and 49.5% for the Trump.

In comparison, the combined PollyVote currently predicts Clinton to gain 52.0% of the popular two-party vote.

Trump slightly favored in updated DeSart model

Jay DeSart updated his long-range model with April polling data. The most recent forecast slightly favors Trump in a likely match-up against Clinton. In particular, the DeSart model predicts Trump to gain 50.9% of the vote, compared to 49.1% for Clinton. Trump is also predicted to win the electoral college with 295 votes, compared to 243 for Clinton.

The vote-share forecast currently enters the combined PollyVote with a weight of 3%. In comparison, today’s PollyVote forecast predicts the Democrats to gain 53.3% of the vote.

Democrats lead by 6 points in latest expert survey

The Pollyvote team has completed its fifth survey of elections experts to forecast the 2016 presidential election. In the late April survey, conducted between April 27 and 30, 15 academics from a variety of colleges and universities responded.

The mean forecast is that the Democrats will garner 53.2% of the major-party vote (compared to 46.8% for the Republicans), with individual forecasts ranging from a minimum of 49.5% to a maximum of 55.2%. Only one expert expected the Republicans to win a majority of the vote.

The predicted Democratic vote share is thus slightly (0.1 percentage points) higher than in the previous survey, conducted in late March, when the mean expert experts had predicted a vote share of 53.1% for the Democrats and 46.9% for the Republicans.

Polly thanks the experts who participated in this round, namely

and one expert who preferred to remain anonymous.

Experts see Democrats’ lead widen

The Pollyvote team has completed its fourth survey of elections experts to forecast the 2016 presidential election. In the late March survey, conducted between March 28 and 31, 14 academics from a variety of colleges and universities responded.

For the first time in this election cycle, all responding experts expected a Democratic win, with forecasts of the popular vote ranging from a minimum of 50.8% to a maximum of 56.8%. The mean forecast is that the Democrats will garner 53.1% of the major-party vote (compared to 46.9% for the Republicans).

The predicted Democratic vote share is thus more than one percentage point higher than in the previous survey, conducted in late February, when the mean expert experts had predicted a vote share of 52.0% for the Democrats and 48.0% for the Republicans.

Polly thanks the experts who participated in this round, namely

and one expert who preferred to remain anonymous.

Issue models turn in Democrats’ favor

After months of no issue polls, an ABC News/Washington Post survey finally provides information about how people rate the candidates’ ability to handle the issues. In particular, the survey asked participants whom of either Clinton or Trump they would expect to do a better job in handling four issues: terrorism (which is currently seen as the most important issue), the economy, immigration, and a potential international crisis.

Participants strongly favored Clinton on all four issues (see Figure). In comparison, prior surveys that asked people to compare Clinton to a generic Republican candidate tended to favor the Republicans. In addition to the bio-index model, this provides further support for the notion that Trump would likely be a poor choice as a nominee for the Republican Party.

The results from the issue questions are used in two models, namely the issue-index and the big-issue models. While, prior to the release of the survey, both models predicted the Republicans to win the popular vote, their forecasts have turned. The issue-index model predicts the Democrats to gain 52.0% of the vote. The big-issue also favors the Democrats, despite predicting a closer race, at 50.6%.