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Probability of Winning 2016 Presidential Election

Check out the Methodology page for details on how we use daily state poll results to arrive at the above probabilities. Updated daily at 8:00am PST.

We have applied this methodology for the past three elections (2004, 2008, and 2012) and in all three elections our calculation correctly predicted the winner and also had a good estimate of the resulting electoral votes for each candidate.

[–]         Compare with 2012 Presidential Election

[+] See 2008 Presidential Election results

[+] See 2004 Presidential Election results

Observations on 2016 Election

  • The graph above includes events that may have influenced the candidates' probability of winning. We have tried to find events that were turning points in the election campaigns. If there are other events that you think caused some of the turning points in the election, please let us know via the contact page or the comment section below.
  • One major caveat on the accuracy of the predictions for 2016 is the effect that Trump and populism have on the accuracy of the polls. Trump has defied several predictions during the Republican primary campaign, and many people came out to vote for him that have not voted in many years. This means that the models that pollsters use to determine who are "likely voters" may not be accurate for this election cycle. We hope that as the election season progresses, pollsters will be able to update and refine their models so that as we get closer to the election, the polls will be more reliable and accurate.

 

  • Another caveat about the results in the plot above for 2016 is that, as of this writing, only 43 states & D.C. have state polls available. For the remaining 8 states, we use the results from the 2012 election. This issue is not expected to have a major effect on the results, because the states that don't yet have polls are not battleground states: they don't have many electoral votes, and the historical voting record shows that one party dominates in these states. We will be updating the results as more polls come in and as we get closer to election day we expect to have polls for all states.


Probability of different electoral vote results



In addition to looking at probabilities of Clinton or Trump winning, we can also look at the probabilities of achieving different electoral vote results. That is, what is the probability that Clinton or Trump will collect say, 270, 285, or 300 electoral votes? (Note that the probability of either of them winning the election is the probability that they will collect 270 or more electoral votes).

The figure on the left shows the probabilities of each of the candidates achieving given electoral vote totals, which vary from zero to 538. The points where the curves are the highest correspond to the most likely electoral votes for each candidate.

As of September 8th, the most likely electoral vote outcome is 309 for Clinton and 229 for Trump.



States with most potential for Clinton upside/Trump downside



It is also instructive to see how sensitive this probability is to changes in state poll results. That is, which states impact the result the most if their polls change in favor of one candidate or another?

In the figure on the left, we see the resulting probability of an Clinton win, given changes in state polls from the five states with the most potential upside for Clinton or downside for Trump.

To keep the figure easy to read, it only includes the resulting probability of an Clinton win. The resulting probability of a Trump win is simply 100 minus the probability of an Clinton win.

As of September 8th, Pennsylvania, Florida, Michigan, New Jersey, and North Carolina have the most potential upside for Clinton. If any of their state polls change by 10% in favor of Clinton (i.e. 5% switch from Trump to Clinton in any state), Clinton's probability of winning increases to around 90%-92% and Trump's probability of winning drops to around 8%-10%.

The results in this plot may not be as informative as one would hope, though. This is due to the fact that this plot shows how the resulting probability of winning changes if a particular state's poll results change by a certain amount. But it doesn't capture the likelihood that that state's poll will change by that amount. Therefore, keep this caveat in mind when interpreting the plot.



States with most potential for Clinton downside/Trump upside



This figure is similar to the previous one, with the only difference being that it corresponds to changes in state polls from the five states with the most potential downside for Clinton or upside for Trump.

Again, to keep the figure easy to read, it only includes the resulting probability of an Clinton win. The resulting probability of a Trump win is simply 100 minus the probability of an Clinton win.

As of September 8th, Texas, Florida, Georgia, Ohio, and South Carolina have the most potential downside for Clinton. If any of their state polls change by 10% in favor of Trump (i.e. 5% switch from Clinton to Trump), Clinton's probability of winning decreases to around 82-84% and Trump's probability of winning jumps to 16-18%.