|95.7% probability of winning||4.3% probability of winning|
|Mean of 303 electoral votes||Mean of 235 electoral votes|
The previous analysis (three days ago) showed President Barack Obama leading Gov. Mitt Romney by a mean of 342 to 196 electoral votes. I was using a 21 day “current poll” window, but promised a shorter one soon. I had previously decided to switch to a 14 day “current poll” window on the 10th of this month, and that is today.
So, for comparison, using a 14 day window three days ago we had Obama leading Romney 316 to 222 electoral votes, and a 99.2% probability of winning an election held then.
Over the past three days, we have 32 new polls that cover 20 states plus each of Maine’s two congressional districts. Most of the polls are post-first-debate. Here are the details:
|ME||Pan Atlantic SMS||24-Sep||28-Sep||400||4.9||50.8||36.8||O+14.0|
|ME1||Pan Atlantic SMS||24-Sep||28-Sep||200||—||52.5||35.4||O+17.1|
|ME2||Pan Atlantic SMS||24-Sep||28-Sep||200||—||49.0||38.1||O+10.9|
The candidates split the Colorado polls, with +1% for Obama and a +4 for Romney. The current polls split three to three between the candidates, giving Romney a very slight edge—a 53% probability of taking the state if the election was now. This is a pretty significant shift as can be seen from the polling history over the past three months:
One new Florida poll has Romney up by +4%. Obama takes four of the six current polls and ends up with a slight edge of a 55% probability of winning now.
Obama gets another small Iowa lead, this time by +2%. He is down to an 85% probability of winning an election now. A week ago, that was a 99% probability….
Obama also holds a small +3% lead in the two new Michigan polls. That is a big drop from the double digit lead he has in the oldest current poll. Still, the evidence suggests Obama would take Michigan in an election now.
Minnesota gives Obama a double digit lead (+10%) in the only post-debate poll for the state.
Romney maintains his strong lead in Montana with this new poll.
Two very close Nevada polls taken together give Obama a very slight lead. Three of the four current polls were taken after the debate and show a very small Obama advantage. The oldest current poll gives Obama a +10%. Here is another view:
Today’s New Hampshire poll has Obama and Romney tied up. This new poll is the only post-debate poll of the three current polls.
New Mexico gives Obama a solid +11% lead over Romney. Essentially, this is as good as Obama was doing before the Debate.
In North Carolina, Romney leads Obama by a single-digit +8.7%. Romney takes three of the five current polls, including both post-debate polls. Romney has a 95% chance in the state for an election now.
Four new polls in Ohio split between Obama and Romney. Combined with four other current polls, Obama ends up with an 86% probability in an election now. Here’s the picture:
Obama keeps the lead in the three new Pennsylvania polls, albeit by smaller margins than he had pre-debate:
Obama leads in the latest Virginia poll. Combined with three other current polls we have a dead even race in the state. The polling history tells the post-debate story:
Obama maintains a weak +2% lead in Wisconsin, where his chances in the state have dropped to 97% for an election now.
Now, after 100,000 simulated elections using a 21 day window, Obama wins 95,666 times and Romney wins 4,334 times (and he get the 347 ties). Obama receives (on average) 303 (-13) to Romney’s 235 (+13) electoral votes. In an election held now, we could expect Obama to win with a 95.7% (-3.5%) probability of winning. That is, Romney surges to a 4.3% probability of winning.
The long term trends in this race can be seen from a series of elections simulated every seven days using polls from 10 Oct 2011 to 10 Oct 2012, and including polls from the preceding 14 days (FAQ).
Here is the distribution of electoral votes [FAQ] from the simulations:
Ten most probable electoral vote outcomes for Obama:
- 304 electoral votes with a 3.80% probability
- 291 electoral votes with a 3.08% probability
- 323 electoral votes with a 2.85% probability
- 310 electoral votes with a 2.75% probability
- 303 electoral votes with a 2.69% probability
- 295 electoral votes with a 2.67% probability
- 320 electoral votes with a 2.57% probability
- 294 electoral votes with a 2.57% probability
- 324 electoral votes with a 2.55% probability
- 311 electoral votes with a 2.52% probability
After 100,000 simulations:
- Obama wins 95.7%, Romney wins 4.3%.
- Average (SE) EC votes for Obama: 303.5 (20.1)
- Average (SE) EC votes for Romney: 234.5 (20.1)
- Median (95% CI) EC votes for Obama: 304 (263, 339)
- Median (95% CI) EC votes for Romney: 234 (199, 275)
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.
|8||4||Votes||polls||Votes||Obama||Romney||% 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.