U.S. Senate Race
03 Nov 2008
| Senate Democrats* | Senate Republicans |
| 100.0% probability of a majority | 0.0% probability of a majority |
| Mean of 59 seats | Mean of 41 seats |
Yesterday’s analysis showed control of the Senate squarely in the hands of the Democrats by 58.7 seats (on average) 41.3 seats for the Republicans.
There were twelve new polls in seven states released today. In aggregate, they very slightly tilt in favor of the Republicans.
After 100,000 simulated elections, Democrats control the senate 100,000 times, there were 0 ties), and Republicans control the Senate 0 times. Democrats have a 100.0% probability of controlling the Senate and Republicans have a 0.0% probability of controlling the Senate.
Here is the distribution of Senate seats from the simulations:*
It looks like there will be 58 or 59 seats in the hands of the Democrats—59 is slightly more probable.
This graphs shows the probability of at least each number of seats controlled by the Democrats:*
- 100000 simulations: Democrats control the Senate 100.0%, Republicans control the Senate 0.0%.
- Average ( SE) seats for Democrats: 58.6 ( 0.6)
- Average (SE) seats for Republicans: 41.4 ( 0.6)
- Median (95% CI) seats for Democrats: 59 (58, 60)
- Median (95% CI) seats for Republicans: 41 (40, 42)
Expected outcomes from the simulations:
- Democratic seats w/no election: 37
- Independent seats w/no election: two
- Republican seats w/no election: 26
- Contested Democratic seats likely to remain Democratic: 12
- Contested Republican seats likely to remain Republican: 16
- Contested Democratic seats likely to switch: none
- Contested Republican seats likely to switch: seven
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 | 54 | |||
| Strong Democrat | 4 | 58 | ||
| Leans Democrat | 0 | 0 | 58 | |
| Weak Democrat | 0 | 0 | 0 | 58 |
| Weak Republican | 1 | 1 | 1 | 42 |
| Leans Republican | 0 | 0 | 41 | |
| Strong Republican | 7 | 41 | ||
| Safe Republican | 34 |
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 |
| Alabama | 1 | 630 | 33.0 | 67.0 | 0.0 | 100.0 | |
| Alaska | 3 | 1409 | 57.1 | 42.9 | 100.0 | 0.0 | |
| Arkansas | 0 | 0 | (100) | (0) | |||
| Colorado | 4 | 3549 | 57.2 | 42.8 | 100.0 | 0.0 | |
| Delaware | 1 | 644 | 67.4 | 32.6 | 100.0 | 0.0 | |
| Georgia | 7 | 4798 | 48.0 | 52.0 | 2.7 | 97.3 | |
| Idaho | 1& | 392 | 42.3 | 57.7 | 1.3 | 98.7 | |
| Illinois | 1& | 744 | 63.4 | 36.6 | 100.0 | 0.0 | |
| Iowa | 3 | 1911 | 63.2 | 36.8 | 100.0 | 0.0 | |
| Kansas | 1 | 583 | 35.5 | 64.5 | 0.0 | 100.0 | |
| Kentucky | 5 | 3079 | 47.1 | 52.9 | 1.2 | 98.8 | |
| Louisiana | 1 | 393 | 59.0 | 41.0 | 99.4 | 0.6 | |
| Maine | 2 | 1150 | 42.4 | 57.6 | 0.0 | 100.0 | |
| Massachusetts | 1 | 606 | 63.0 | 37.0 | 100.0 | 0.0 | |
| Michigan | 3 | 3061 | 61.6 | 38.4 | 100.0 | 0.0 | |
| Minnesota | 7 | 3941 | 50.0 | 50.0 | 48.9 | 51.1 | |
| Mississippi | 2 | 1055 | 45.4 | 54.6 | 1.9 | 98.1 | |
| Mississippi | 1& | 455 | 35.2 | 64.8 | 0.0 | 100.0 | |
| Montana | 1 | 2652 | 73.2 | 26.8 | 100.0 | 0.0 | |
| Nebraska | 1& | 450 | 42.2 | 57.8 | 1.0 | 99.0 | |
| New Hampshire | 10 | 5804 | 54.9 | 45.1 | 100.0 | 0.0 | |
| New Jersey | 5 | 3217 | 59.1 | 40.9 | 100.0 | 0.0 | |
| New Mexico | 4 | 3232 | 58.5 | 41.5 | 100.0 | 0.0 | |
| North Carolina | 11 | 8100 | 52.9 | 47.1 | 100.0 | 0.0 | |
| Oklahoma | 2 | 1211 | 42.0 | 58.0 | 0.0 | 100.0 | |
| Oregon | 6 | 4026 | 53.6 | 46.4 | 99.9 | 0.1 | |
| Rhode Island | 1& | 460 | 78.3 | 21.7 | 100.0 | 0.0 | |
| South Carolina | 1 | 634 | 40.2 | 59.8 | 0.0 | 100.0 | |
| South Dakota | 1& | 552 | 62.0 | 38.0 | 100.0 | 0.0 | |
| Tennessee | 1& | 576 | 38.5 | 61.5 | 0.0 | 100.0 | |
| Texas | 1& | 475 | 42.1 | 57.9 | 0.7 | 99.3 | |
| Virginia | 6 | 4623 | 64.2 | 35.8 | 100.0 | 0.0 | |
| West Virginia | 1 | 2085 | 59.2 | 40.8 | 100.0 | 0.0 | |
| Wyoming | 1 | 485 | 36.1 | 63.9 | 0.0 | 100.0 | |
| Wyoming | 1 | 475 | 36.8 | 63.2 | 0.0 | 100.0 |
@ Current party in office
& An older poll was used (i.e. no recent polls exist).
*Analyses assume that independent Senators Sanders and Lieberman continue to caucus with the Democrats.
Details of the methods are given in the FAQ.
The most recent analysis in this and other elections can be found from this page.
