How the House forecast works

District election history, incumbency, fundraising, and the adjusted national generic ballot form a fundamentals baseline. Where qualifying polling is available, that baseline is blended with the polling margin using poll count, age, and time to Election Day.

Each simulated election shares a national error and state errors. District errors preserve local uncertainty. Control is counted at 218 seats in each simulated election.

The current uncertainty parameters are provisional and have not completed historical calibration. This version models Democratic–Republican matchups. Publication requires reviewing district coverage and matchup exceptions.