The overall numbers haven’t changed much since my previous analysis last Saturday. The “score” still remains 54 to 46 in favor of the Democrats, if the election had been held today.
This analysis is based on a Monte Carlo analysis with 100,000 simulated elections. The results were that Democrats had a Senate majority 99,878 times and there were 122 ties. Republicans controled the Senate 0 times. If the election was today and Biden won, Democrats would control the Senate with a >99.99% probability. If Biden loses, the Democrat’s chances drop to 99.88%
Even if the overall numbers have changes, there are some interesting results from individual states. I’ll compare movement over the past 5 days.
- Alaska—One new PPP poll (for a total of 4) favors Republican Sen. Dan Sullivan. His chances bump up from a 52% probability to a 65% probability of defeating Democrat Al Gross
- Georgia seat 1—We have six new polls and lose four old polls for a total of 17 polls. The result is that the race changes from a 60% probability of Republican Sen. David Perdue winning to a 61% probability of Democrat Jon Ossoff winning
- Iowa—The race with Democrat Theresa Greenfield trying to unseat Republican Sen. Joni Ernst sees two new polls and two old polls drop out. The net result, with 12 polls, is that Greenfield goes from a 76% to a 87% probability of winning right now
- Kansas—This is one of the big surprises for 2020 where Democrat Barbara Bollier may well defeat Republican Roger Marshall for this open seat. One poll aged out, leaving three poll that moves Bollier from a 63% to an 81% probability of winning. One caveat…the newest of the three current poll has Marshall in the lead.
- Maine—The race with Democrat Sara Gideon trying to unseat Republican Sen. Susan Collins has generally favored Gideon. With two new polls and one old poll dropping out, the four current polls all have Gideon in the lead, but her chances drop from 97% to 88%. The primarily reason is a new SurveyUSA poll that has Gideon leading by a mere 0.4%!
- Mississippi—This race has Democrat Mike Espy trying to unseat Republican Sen. Cindy Hyde-Smith. Five days ago, the only poll was from last August and had Hyde-Smith up by +1. A new Civiqs poll has her up by +8, upping her chances from 56% to 90%.
- Montana—This contest between Democrat Steve Bullock and Republican Sen. Steve Daines is another surprisingly close race. Keep an eye on it. We have two new polls weighing in for a total of eight polls. Four polls have Daines leading, three polls have Bullock leading (by +1), and there is one tie. Daines chances drop from 80% to 71% of winning an election held now.
- South Carolina—This is the race everyone is watching to see if Democrat Jamie Harrison will dethrone Republican Sen. Lindsey Graham. Graham was barely hanging on with a 57% probability of winning, but with three new polls added in and two dropping out (for a total of 6 polls), Graham’s chances have risen to 87% probability. Three of the polls favor Graham, two favor favor Harrison and there is one tie.
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 100.0%, Republicans control the Senate 0.0%.
- Average ( SE) seats for Democrats: 54.2 ( 1.3)
- Average (SE) seats for Republicans: 45.8 ( 1.3)
- Median (95% CI) seats for Democrats: 54 (52, 57)
- Median (95% CI) seats for Republicans: 46 (43, 48)
Expected outcomes from the simulations:
- Democratic seats w/no election: 34
- Independent seats w/no election: one
- Republican seats w/no election: 30
- Contested Democratic seats likely to remain Democratic: 11
- Contested Republican seats likely to remain Republican: 16
- Contested Democratic seats likely to switch: one
- 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|
This table summarizes the results by state. Click on the poll number to see the individual polls included for a state.
|State||@||polls||size||Democrat||Republican||% wins||% wins|
@ Current party in office
& An older poll was used (i.e. no recent polls exist).
*Analysis assume that the two independent candidates will caucus with the Democrats.
Details of the methods are given in the FAQ.
The most recent analysis in this match-up can be found from this page.