PredictIt is a U.S.-based prediction market and SBK is a British sports betting app, but both are indicating that political gamblers see Republicans making gains in the U.S. Senate this year (at least as of Friday, February 4, 2022). The probabilities in the 12 Senate races where both platforms are currently accepting action are extremely close and no more than 0.02 apart.
PredictIt offers binary option contracts: an event either happens or does not happen (Yes or No). A correct prediction receives $1/share, and a wrong prediction receives $0/share. PredictIt traders can buy shares on which party (defined as “Democratic” or “Republican”) will win a state in a particular U.S. Senate election. SBK offers gambling odds that represent the potential net profit for the amount wagered (“stake”). PredictIt share prices represent the probability that traders believe an event will happen and SBK odds can be converted to implied probabilities. You can read more about how I compare share prices and odds in an earlier article.
Both PredictIt share prices and SBK implied probabilities show incumbent Democratic Senators in Arizona, Georgia, and Nevada losing to Republicans this fall:
| REP | REP | DEM | DEM | ||
| State | PredictIt | SBK | PredictIt | SBK | Incumbent |
| Arizona | 0.62 | 0.62 | 0.38 | 0.40 | Kelly |
| Georgia | 0.60 | 0.60 | 0.44 | 0.44 | Warnock |
| Nevada | 0.56 | 0.57 | 0.46 | 0.46 | Cortez Masto |
Traders on both platforms are also betting that Republicans hold onto four seats where the incumbent Republican is retiring:
| REP | REP | DEM | DEM | |
| State | PredictIt | SBK | PredictIt | SBK |
| Missouri | 0.92 | 0.92 | 0.08 | 0.09 |
| North Carolina | 0.80 | 0.81 | 0.20 | 0.20 |
| Ohio | 0.84 | 0.86 | 0.16 | 0.16 |
| Pennsylvania | 0.64 | 0.65 | 0.38 | 0.38 |
Of those 12 Senate races, only New Hampshire is currently favoring the Democrat:
| REP | REP | DEM | DEM | ||
| State | PredictIt | SBK | PredictIt | SBK | Incumbent |
| New Hampshire | 0.46 | 0.48 | 0.56 | 0.56 | Hassan |
In Alaska, where Republican incumbent Senator Lisa Murkowski is seeking re-election, gamblers see an Independent as having a better chance of winning than a Democratic candidate:
| REP | REP | IND | IND | DEM | DEM | ||
| State | PredictIt | SBK | PredictIt | SBK | PredictIt | SBK | Incumbent |
| Alaska | 0.90 | 0.89 | 0.07 | 0.08 | 0.04 | 0.05 | Murkowski |
In the remaining three states, political traders and gamblers both see Republican incumbents easily retaining their seats in Florida, Iowa, and Wisconsin:
| REP | REP | DEM | DEM | ||
| State | PredictIt | SBK | PredictIt | SBK | Incumbent |
| Florida | 0.90 | 0.92 | 0.11 | 0.11 | Rubio |
| Iowa | 0.94 | 0.94 | 0.07 | 0.08 | Grassley |
| Wisconsin | 0.70 | 0.71 | 0.30 | 0.31 | Johnson |
In the 2020 Presidential election, implied probabilities for odds offered by British bookmakers had a lower Brier score than PredictIt share prices. It will be interesting to see if that holds up in this year’s Senate midterm elections when there presumably will be less interest and lower volume.