US Senate Probability Tracker – An AI Agent for Political Junkies! (copy)
US Senate Probability Tracker – An AI Agent for Political Junkies!
Net: Using Claude, we developed an AI agent that forecasts the outcome of the 16 contested 2026 US Senate Races. It automatically updates when a new credible poll is released in any of the contested races and forecasts both the outcome of the 16 races and the post-election party affiliation of the US Senate under the following scenarios:
- Latest poll accurately reflects the final outcome.
- Latest average of recent polls reflects the final outcome.
- The polls overstate the actual Democratic vote by 2.5%, based on the historical poll/ vote discrepancy for all Senate elections held between 2014 and 2024.
- The polls overstate the actual Democratic vote by 0.6%, based on the average vote discrepancy for midterm Senate races.
- The polls overstate the actual Democratic vote by 5.8%, the largest discrepancy during 2014-2024, and it occurred in 2020.
The Details:
We hypothesized that election polls over the past decade+ often overstated the final Democratic vote. Claude Cowork analysis confirmed this hypothesis, with the overstatement of Democratic votes in polls vs. final vote totals ranging from 0.6% (midterm elections from 2014-2024) to 5.8% (2020). We then used Claude to create an agent that runs the 5 scenarios listed above every time a new credible poll is released. Here is a summary of the latest model, as of October 9, 2026:
And here are the individual outcomes for each of the 16 states:
Please email craig@underwoodpartners or DM me if you would like to be on the distribution list for this sensitivity analysis whenever it is updated with a new poll from any of the 16 contested states. Thanks!
