|100.0% probability of winning||0.0% probability of winning|
|Mean of 341 electoral votes||Mean of 197 electoral votes|
Beginning this analysis, I’ve narrowed the “current polling window.” The old window included all polls taken within the past month. That criterion resulted in some states with many “current” polls, including some pre-conventions polls.
The new criterion is three weeks, so that almost all the polling occurs after the conventions. You can expect the window to shrink to two weeks sometime in October.
There are two effects from shrinking the window. First, the number of individuals polled goes down for some states. With fewer respondents, we have less evidence and, therefore, uncertainty increases (all else being equal).
The other effect is that there is less smoothing of the results. That is, the results become more indicative of trends.
Taken together, we might expect that Governor Mitt Romney’s chances improve through the increase in uncertainty. We can also expect Romney’s chances to decrease as a result of a recent poll surge for Obama. As it happens, the latter has a much stronger effect. The net effect is that Romney takes a beating….
The previous analysis had Obama leading Romney by 331 to 207 electoral votes, and the analysis suggested that Obama would almost certainly win an election held now.
Nineteen new polls covering 13 states have appeared in the past two days. Additionally, I’ve found four older polls (one each in AL, CO, OH, and FL) by comparing my database against Samuel Minter’s database.
Here are the new polls:
|AR||Talk Business-Hendrix College||17-Sep||17-Sep||2228||2.0||34.5||55.5||R+21.0|
With this new poll, seven of eight current Colorado polls go to Obama suggesting he would win an election now with about a 95% probability. One can sense from the last three months of polling that Obama is gaining slowly in the state:
Florida has Obama up by +4% in two new polls and +5 in another. Obama has now led in five consecutive polls in the state. That trend we can almost discern in Colorado is even more apparent in Florida:
Romney took the previous Iowa poll, but this new one goes +7% for Obama. The three current polls, take together, suggest Obama has a 95% chance of taking the state right now.
Another solid Michigan poll for Obama leaves him with a certain win in the state (at least, for now).
The Civitas Institute is a right wing think tank in North Carolina, but they release all their polls. This one has Obama leading by +4%. Obama leads in four of the six current polls and the last three in a row. Still, the weight of evidence goes very slightly to Romney. The trend seems to be in Obama’s favor:
Obama gets his best and his worst poll in recent months in today’s Pennsylvania collection. Still, it is hard to argue that Obama’s lead isn’t solid:
Finally, a double-digit lead for Obama in Wisconsin caps off a very favorable collection of recent polls in the state for the President. Whatever momentum Romney had in the state in August seems to have almost entirely vanished:
Now after 100,000 simulated elections, Obama wins 100,000 times and Romney wins 0 times. Obama receives (on average) 341 (+10) to Romney’s 197 (-10) electoral votes. In a hypothetical election held now, Obama would have a 100.0% probability of winning.
Here is the distribution of electoral votes [FAQ] from the simulations:
Ten most probable electoral vote outcomes for Obama:
- 335 electoral votes with a 6.76% probability
- 336 electoral votes with a 6.59% probability
- 346 electoral votes with a 5.98% probability
- 350 electoral votes with a 5.26% probability
- 345 electoral votes with a 4.92% probability
- 351 electoral votes with a 4.54% probability
- 332 electoral votes with a 4.36% probability
- 347 electoral votes with a 4.05% probability
- 331 electoral votes with a 3.81% probability
- 341 electoral votes with a 2.77% probability
After 100,000 simulations:
- Obama wins 100.0%, Romney wins 0.0%.
- Average (SE) EC votes for Obama: 341.0 (13.1)
- Average (SE) EC votes for Romney: 197.0 (13.1)
- Median (95% CI) EC votes for Obama: 342 (310, 363)
- Median (95% CI) EC votes for Romney: 196 (175, 228)
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.