Call
the Map
FORECAST55 DAYS OUT

Changelog

Material changes, dated and stated plainly. Routine source refreshes do not get dressed up as product announcements.

September 2026

model

The model version changed to CTMM 2.1

The published forecast moved from CTMM v1 to CTMM 2.1. Every race centre, chamber probability and interval on the site now comes from the new model.

  • CTMM 2.1 rebuilds the centres on validated v2 fundamentals, adds G1 governor calibration and core-plus-tail uncertainty for the House and Governor boards, and restores the v2 architecture for the Senate. Two House data defects were repaired with it: twelve seats carried a holding party taken from the sign of a reconstructed prior rather than from the member defending the seat, and fourteen were contaminated by 2024 districts that had no candidate from one major party. No calibration layer was adopted; nested leave-one-cycle-out testing rejected every candidate, so the identity stands.
  • Because the model version changed, the public history series restarts here. Readings from before this date remain in the archive and are not joined to readings after it: a line drawn across a model change measures the model, not the race.
publication

Launch

Call the Map opens with forecasts for all 435 U.S. House districts, 35 Senate seats and 36 governorships, from the sealed edition ctm-1.0-20260906-25e5a4bb5f67.

  • Every race page shows a chance of winning, a projected margin where the candidate field supports one, the middle-80% range, and the evidence behind the estimate.
  • The full methodology is published in two forms: a plain-language guide and the technical document with every equation and fitted coefficient.
  • Corrections that change a published number will be recorded on this page and in the edition record on the About page, with the edition they landed in.