Well…a lot can happen in a month. I’ve been rather negligent in gathering polling data and doing these analyses, so here we are on Election Day Eve. I’ll post an analysis based on polls collected through about 5pm today. If there are more polls tomorrow morning, there will be a final analysis tomorrow early afternoon or so.
My last analysis, about a month ago, found Democrats “in the lead” with a 97% probability of taking the Senate (if the election had been held then, that is). Lots and lots of new polls have been published. And it seems that pollsters have been procreating new baby pollsters between election seasons.
Taken altogether, after 100000 simulated elections, Democrats have a Senate majority only 1,086 times, (and there were 12,193 ties), and Republicans control the Senate 86,721 times.
What this suggests is that Democrats have a 13.3% probability of controlling the Senate and Republicans have a 86.7% probability of controlling the Senate, based only on the last two weeks of polling data (when available…older polls are used if necessary). That is quite the shift over a month.
There is a bit of good news for Democrats. Incumbent Mark Kelly (D-AZ) has a solid lead over his opponent, Blake Masters. Likewise, Colorado, New Hampshire and Washington seem safe for the Democratic incumbents.
Things are not so good for Democrats in Georgia, where Sen Raphael Warnock (D) is, essentially, tied with Herschel Walker. Bizarre, huh? In Nevada, Sen Cortez Masto’s (D) race has turned around and Adam Laxalt (R) might well be looking for a flat in D.C. soon.
Likely Democratic pick-ups have all but vanished. Rep. Tim Ryan (D-OH-13) once led Republican J.D. Vance for the Ohio Senate race. But Vance has led in 7 of the 8 polls taken in the past 14 days. In Pennsylvania, the Senate race between John Fetterman (D) and Mehmet Oz (R) has tightened, and Oz now holds a very slight lead. Wisconsin? Fuggitaboudit. Sen. Ron Johnson (R) is headed back to D.C. Florida? Not even close. Sen. Marco Rubio (R) will have the privilege of six more years of the job he hates.
Are the polls underestimating chances for Democrats? Maybe. The buzz in the poll aggregation community is that right-leaning pollsters have “flooded the zone” with polls bearing right-skewed results over the past several weeks. Why would they even do that? Wouldn’t that just make them look bad after the election? Either way, tomorrow is going to be “interesting.”
Here is the distribution of Senate seats from the simulations:*
This graphs shows the probability of at least each number of seats controlled by the Democrats:*
- 100000 simulations: Democrats control the Senate 13.3%, Republicans control the Senate 86.7%.
- Average ( SE) seats for Democrats: 48.5 ( 1.0)
- Average (SE) seats for Republicans: 51.5 ( 1.0)
- Median (95% CI) seats for Democrats: 48 (47, 50)
- Median (95% CI) seats for Republicans: 52 (50, 53)
Expected outcomes from the simulations:
- Democratic seats w/no election: 34
- Independent seats w/no election: two
- Republican seats w/no election: 29
- Contested Democratic seats likely to remain Democratic: 12
- Contested Republican seats likely to remain Republican: 21
- Contested Democratic seats likely to switch: two
- Contested Republican seats likely to switch: none
This table shows the number of Senate seats controlled for different criteria for the probability of winning a state:* Safe>0.9999, Strong>90%, Leans>60%, Weak>50%
| Threshold | Safe | + Strong | + Leans | + Weak |
|---|---|---|---|---|
| Safe Democrat | 44 | |||
| Strong Democrat | 2 | 46 | ||
| Leans Democrat | 2 | 2 | 48 | |
| Weak Democrat | 0 | 0 | 0 | 48 |
| Weak Republican | 1 | 1 | 1 | 52 |
| Leans Republican | 1 | 1 | 51 | |
| Strong Republican | 9 | 50 | ||
| Safe Republican | 41 |
This table summarizes the results by state. Click on the poll number to see the individual polls included for a state.
| # | Sample | Percent | Percent | Democrat | Republican | ||
|---|---|---|---|---|---|---|---|
| State | @ | polls | size | Democrat | Republican | % wins | % wins |
| AL | 0 | 0 | (0) | (100) | |||
| AK | 0 | 0 | (0) | (100) | |||
| AZ | 16 | 11772 | 51.1 | 48.9 | 94.5 | 5.5 | |
| AR | 1& | 451 | 32.2 | 67.8 | 0.0 | 100.0 | |
| CA | 0 | 0 | (100) | (0) | |||
| CO | 4 | 3028 | 54.8 | 45.2 | 100.0 | 0.0 | |
| CT | 1 | 773 | 66.2 | 33.8 | 100.0 | 0.0 | |
| FL | 7 | 4408 | 46.2 | 53.8 | 0.0 | 100.0 | |
| GA | 15 | 12247 | 49.9 | 50.1 | 46.3 | 53.7 | |
| HI | 0 | 0 | (100) | (0) | |||
| ID | 0 | 0 | (0) | (100) | |||
| IL | 1 | 441 | 59.2 | 40.8 | 99.5 | 0.5 | |
| IN | 1 | 615 | 43.7 | 56.3 | 1.4 | 98.6 | |
| IA | 1 | 753 | 43.6 | 56.4 | 0.8 | 99.2 | |
| KS | 1 | 868 | 37.6 | 62.4 | 0.0 | 100.0 | |
| KY | 1& | 588 | 41.5 | 58.5 | 0.1 | 99.9 | |
| LA | 0 | 0 | (0) | (100) | |||
| MD | 1& | 666 | 62.9 | 37.1 | 100.0 | 0.0 | |
| MO | 5 | 4295 | 44.0 | 56.0 | 0.0 | 100.0 | |
| NV | 9 | 6281 | 48.2 | 51.8 | 2.5 | 97.5 | |
| NH | 9 | 10733 | 50.7 | 49.3 | 84.4 | 15.6 | |
| NY | 5 | 4024 | 60.1 | 39.9 | 100.0 | 0.0 | |
| NC | 7 | 6807 | 47.4 | 52.6 | 0.1 | 99.9 | |
| ND | 0 | 0 | (0) | (100) | |||
| OH | 8 | 7425 | 46.9 | 53.1 | 0.0 | 100.0 | |
| OK | 3 | 2024 | 41.6 | 58.4 | 0.0 | 100.0 | |
| OK | 3 | 1984 | 38.8 | 61.2 | 0.0 | 100.0 | |
| OR | 2 | 2171 | 58.2 | 41.8 | 100.0 | 0.0 | |
| PA | 14 | 11479 | 49.8 | 50.2 | 37.0 | 63.0 | |
| SC | 1& | 546 | 40.7 | 59.3 | 0.1 | 99.9 | |
| SD | 1& | 1275 | 31.8 | 68.2 | 0.0 | 100.0 | |
| UT | 2 | 1242 | 43.2 | 56.8 | 0.1 | 99.9 | |
| VT | 1& | 987 | 66.4 | 33.6 | 100.0 | 0.0 | |
| WA | 3 | 2183 | 51.1 | 48.9 | 76.1 | 23.9 | |
| WI | 8 | 6410 | 48.5 | 51.5 | 3.8 | 96.2 |
@ Current party in office
& An older poll was used (i.e. no recent polls exist).
*Analysis assume that independent candidates will caucus with the Democrats.
Details of the methods are given in the FAQ.
