Corrections Log
Every material correction to the model, the data, or a published forecast since launch. The point of this page is radical transparency: any forecast you read today links to the version of the model that produced it, and any prior call can be reproduced.
CivicTrust registration_rate inverse-signal bug (v11c -> v11d)
2026-06-01 | Methodology
The Census CPS Voting Supplement question PES2 (voter registration status) is only asked of self-reported non-voters. Our earlier ingestor computed regPct = pes2_yes / (pes2_yes + pes2_no), which inverted the signal: states with high turnout produced low registration rates. The corrected formula counts voters as presumed-registered: regPct = (voters + non-voter_yes) / total. Combined with switching turnout source from CPS turnout_delta to MIT EL absolute senate turnout, and replacing the binary state_lean with a continuous presidential margin, v11d shipped at test_brier 0.135. The prior v11c (0.114) was a broken-data ceiling and has been retired from the publishable selector along with all pre-fix variants.
Information_candidates feature clip (v9 -> v10)
2026-05-31 | Methodology
The Information dimension's candidate-quality sub-feature was missing a sign-flip on incumbent contests, producing P(D) drift on uncontested seats. v10 added a clip and re-calibrated. Brier moved 0.137 to 0.135 on the 2024 holdout.