|98.9% probability of winning||1.1% probability of winning|
|Mean of 311 electoral votes||Mean of 227 electoral votes|
Huh. Four years ago at this time, I was frantically entering the eleven new polls that had come out on election day. Today…not so much. We get only one rather inconsequential poll, although because it is Maine, and the Congressional districts are reported, we get three new polls for the price of one.
As a consequence, this analysis differs little from yesterday’s analysis.
After 100,000 simulated elections, Obama wins 98,946 times and Romney wins 1,054 times (including the 180 ties). Obama received (on average) 311 (+2) to Romney’s 227 (-2) electoral votes. In an election held now, Obama would have a 98.9% (+0.1%) probability of winning and Romney would have a 1.1% (-0.1%) probability of winning.
My prediction: Obama wins. It’s almost certain.
Here’s our look back over the race from a series of elections simulated every seven days using polls from 06 Nov 2011 to 06 Nov 2012, and including polls from the preceding seven days (FAQ).
The interesting thing is the very ragged, multimodal distribution of electoral votes seen in the graph below. The single most likely outcome in this race is an Obama victory with 303 electoral votes. There is a 9.2% probability of that happening.
Then it jumps to 332 electoral votes, with a 6% probability. And then to 318 electoral votes with a 3.8% probability. And so on.
The raggedness of the electoral votes distribution reflects that there are a non-trivial number of important states with large uncertainty. Florida is Romney’s but with only a 63% probability. Iowa is Obama’s but with only an 84% probability. North Carolina is in Romney’s column, but with a 74% probability, and Virginia goes to Obama, but with a 78% probability.
Ten most probable electoral vote outcomes for Obama (full distribution here):
- 303 electoral votes with a 9.19% probability
- 332 electoral votes with a 5.94% probability
- 318 electoral votes with a 3.80% probability
- 304 electoral votes with a 3.78% probability
- 290 electoral votes with a 3.49% probability
- 319 electoral votes with a 3.30% probability
- 297 electoral votes with a 2.97% probability
- 314 electoral votes with a 2.30% probability
- 312 electoral votes with a 2.23% probability
- 333 electoral votes with a 2.11% probability
After 100,000 simulations:
- Obama wins 98.9%, Romney wins 1.1%.
- Average (SE) EC votes for Obama: 310.7 (19.3)
- Average (SE) EC votes for Romney: 227.3 (19.3)
- Median (95% CI) EC votes for Obama: 308 (276, 347)
- Median (95% CI) EC votes for Romney: 230 (191, 262)
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.