[18 September 2020]
My previous analysis was before the conventions. Now, roughly a month after the conventions, any movement from the conventions should become apparent.
To assess an election held today, we simulate 100,000 elections using the past month of polls as “current” and only using older polls if there are no current polls. From that exercise, Joe Biden won all 100,000. Biden received (on average) 389 to Donald Trump’s 149 electoral votes, a modest improvement for Biden from the 378 to 160 electoral vote lead he had at the end of July. In an election held now, Biden would have a greater than 99.9% 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 18 Sep 2019 to 18 Sep 2020, and including polls from the preceding month (FAQ).
Clearly, Biden has the lead and the momentum at this point in the election season, with his expected electoral vote total tending to climb since January. Details for the the most recent simulation is found below the fold.
Here is the distribution of electoral votes [FAQ] from the simulations for today’s results:
Ten most probable electoral vote outcomes for Biden (full distribution here):
- 407 electoral votes with a 4.51% probability
- 389 electoral votes with a 3.58% probability
- 413 electoral votes with a 3.51% probability
- 395 electoral votes with a 2.56% probability
- 392 electoral votes with a 2.53% probability
- 408 electoral votes with a 2.52% probability
- 406 electoral votes with a 2.46% probability
- 403 electoral votes with a 2.40% probability
- 398 electoral votes with a 2.23% probability
- 391 electoral votes with a 2.17% probability
The single most likely outcome is a 407 to 131 victory for Biden. Many, if not all, of those outcomes would be considered a landslide victory depending, of course, on the definition of a landslide.
Further results from 100,000 simulations:
- Biden wins greater than 99.9%, Trump wins less than 0.1%.
- Average (SE) EC votes for Biden: 389.4 (20.6)
- Average (SE) EC votes for Trump: 148.6 (20.6)
- Median (95% CI) EC votes for Biden: 392 (344, 419)
- Median (95% CI) EC votes for Trump: 146 (119, 194)
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.
|6||2||Votes||polls||Votes||Biden||Trump||% wins||% wins|
* An older poll was used (i.e. no recent polls exist).
Details of the methods are given in the FAQ.