Update September 26, 2016
Probability of Clinton Win: 72% | Probability of Trump Win: 28%
Clinton – Trump Spread: 2.3%
Clinton’s slide continued over the week. On the eve of the first debate, the two candidates are close, but Clinton still has a lead, although clearly not insurmountable. Even without any change in sentiment, there is enough noise in the data that Trump credibly win the election. We note that Nate Silver at FiveThirtyEight has the win probability at roughly 50% / 50%. Our model suggests that Nate’s is off at this stage.
Update September 20, 2016
Probability of Clinton Win: 82% | Probability of Trump Win: 18%
Clinton – Trump Spread: 3.6%
A massive poll (>13,000 observations) from NBC/SurveyMonkey has Clinton leading by 5%. This has provided Clinton with a soft landing from a rather bad couple of weeks of polling.
We also show below the noise from the various polling companies relative to our average: see below (the 50% level represents the average). Most companies are spread around the mean with just a few outliers. A number above 50% suggests that the polling group favors Clinton, a number below 50% suggests Trump is favored. However, the credible intervals are roughly about 2%, suggesting that there could well be about 2% noise between the eventual / final poll results and the actual election.
September 16, 2016
Probability of Clinton Win: 75% | Probability of Trump Win: 25%
Clinton – Trump Spread: 2.8%
Despite some very poor polling over the last couple of days, our model has Clinton at a 75% probability of leading. This in reality means that the race is really close! There is enough uncertainty about the basis risk between the polls and the actual election that Trump could plausibly win the election.
We note that the Clinton win probability has not fallen to a 50% level despite some polls having the race all tied up, as the model is stilling “borrowing strength” from some of the older polls where Clinton was leading. Look for this to change, if Trumps strong performance continues.
At this stage, Trump has pretty much reversed the lead that Clinton took post her convention, and brought the race into striking distance.
