We have now had a few days for post-debate polls to trickle out. My previous analysis, four days ago, was almost entirely pre-debate polls. It showed Clinton with a 79.2% probability of winning the election with, on average, 288 electoral votes.
There have been about 20 or so post-debate state head-to-head polls released, mostly in competitive states. The results confirm the general wisdom that Clinton gained the edge from the first debate.
Today, after 100,000 simulated elections, Clinton wins 92,456 times and Trump wins 7,544 times (including the 1,007 ties). Clinton received (on average) 300 to Trump’s 238 electoral votes. In an election held now, Clinton would have a 92.5% probability of winning and Trump would have a 7.5% probability of winning.
A couple of states showed some interesting changes:
In Colorado one poll aged out and we got two new polls today that both have Clinton up by +11%. This has moved the probability from 51.4% for Trump to 83.7% for Clinton. The state is still quite close, but the magnitude of Clinton’s lead in two polls suggest that Clinton now has the advantage.
The story is similar in Florida one poll aged out, and three new polls were released, all with Clinton leading. Clinton’s leads, however, are smaller at 4%, +0.2% and 5%. Clinton is leading in 6 of the 10 current polls. Trump had a 60.6% probability of taking Florida 4 days ago, now Clinton is up with a 62.9% probability. The state is still mighty close!
Trump gains a bit in Iowa, not because of any new polls—there have been none since the debate. Rather one poll aged out. Trump leads in 2 of the 3 current Iowa polls.
Nevada gains two new polls with Clinton up by +6% and +1%. As a result Trump’s probability of winning of 66.8% four days ago has shrunk to 47.6%. This is, basically, a tie.
New Hampshire is over-polled because of a competitive Senate race. We lost one poll and gained two new ones in 4 days with Clinton up +6% and +7%. Clinton’s chances go up a bit to a 99.1% probability of winning today.
We have one new poll in New Jersey for a total of 2 polls. This one has Clinton up 6.4%, and so Clinton moves from a 78.3% probability to a 92.5% probability of taking the state.
In New Mexico, one old poll was replaced by a new (but small) poll that has Clinton up +4%. The previous poll had her at +9%. As a result, Clinton’s chances have dropped from 99.4% to 77.3% probability of winning the state now. The polling history suggests that Clinton is very likely to take New Mexico:
Two new polls, and the loss of an old poll in North Carolina have strengthened Clinton’s tenuous hold on the state. She now has lead in five consecutive NC polls, but the margins are small (+1%, +3%, +1%, +2.6% and +1%). Her chances have gone from 52.2% to 56.7%. Still, pretty much a tie.
In Pennsylvania we lose two polls and gain one new one. This has tightened the race slightly, but Clinton still has a 94.9% probability of taking the state. The polling history does suggest a tightening of the race, but Clinton leads the last 5 polls by small margins (+4%, +3%, +1%, +2%, +2%).
Virginia loses one poll and gains two new ones. Four days ago, Clinton had a 99.7% probability of winning. Today, she takes all but 28 of the 100,000 simulated elections.
The long term trends in this race can be seen from a series of elections simulated every seven days using polls from 03-Oct-2015 to 03-Oct-2016, and including polls from the preceding month (FAQ). As we’ve seen before, Clinton is on the move upward, after hitting a “low” that still had her most likely winning the election.
Note that the polls have yet to “speak” to Donald Trump’s other problems that arose after the debate—his 3am tweet about an Hispanic model (Alicia Machado) and her non-existent “sextape”, Trump’s own soft-core porn video, Trump’s suggestion that his opponent is cheating on her spouse, Trump’s partial 1995 tax forms showing over $900 million losses, the Trump Foundation’s potential legal problems, his badly-stated comment about Vets with PTSD, and a bunch of high profile newspaper non-endorsements. If these issues affect the polls, we’ll see the effects over the next week or two.
Of course, things may not continue to favor Clinton. Wednesday is supposedly the “October Surprise” that will un-do her.
An animated sequence of maps and electoral vote distributions can be seen here
Here is the distribution of electoral votes [FAQ] from the simulations:
Ten most probable electoral vote outcomes for Clinton (full distribution here):
- 307 electoral votes with a 3.41% probability
- 322 electoral votes with a 2.83% probability
- 318 electoral votes with a 2.75% probability
- 293 electoral votes with a 2.65% probability
- 289 electoral votes with a 2.62% probability
- 301 electoral votes with a 2.56% probability
- 316 electoral votes with a 2.55% probability
- 304 electoral votes with a 2.42% probability
- 312 electoral votes with a 2.35% probability
- 278 electoral votes with a 2.25% probability
After 100,000 simulations:
- Clinton wins 92.5%, Trump wins 7.5%.
- Average (SE) EC votes for Clinton: 300.4 (20.9)
- Average (SE) EC votes for Trump: 237.6 (20.9)
- Median (95% CI) EC votes for Clinton: 302 (259, 339)
- Median (95% CI) EC votes for Trump: 236 (199, 279)
Each column of this table shows the electoral vote total aggregated by different criteria for the probability of winning a state (Safe=100%, Strong=90%+, Leans=60%+, Weak=50%+):
|Threshold||Safe||+ Strong||+ Leans||+ Weak|
This table summarizes results by state. Click on the poll count to see the individual polls included for the state.
|2||8||Votes||polls||Votes||Clinton||Trump||% wins||% wins|
* An older poll was used (i.e. no recent polls exist).
Details of the methods are given in the FAQ.
The most recent analysis in this match-up can be found from this page.