What this site covers
This page explains the methods behind the five public Catalyst pages:
- Forecast: the 2026 House, Senate and governor forecast described on this page.
- Race reports: one page per competitive contest, built from the same forecast inputs plus sourced polls and FEC filings.
- Redistricting: maps redrawn in 2025–26, each linked to its public source.
- Money: campaign receipts and spending from FEC filings, with the filing date shown.
- Home: an overview of the Catalyst platform and its data standard.
Every number carries one of four labels: LIVE, SOURCED, ESTIMATED or ANALYST. Gaps are shown as gaps.
Catalyst v2.1 forecast
Where every poll and forecaster places control
One row per chamber. Each source sits in its lane; the bold accent line is the Catalyst forecast. How to read these charts ↓
Race by race
Forecaster report cards
Forecaster Scorecard
v2.1 Scorecard
Tipping-point races
Scenarios
v2.1 Calibration
Backtest and Calibration
How to read these charts
Each row shows one chamber. Left to right is the chance Democrats win control (0–100%, gridlines every 10%, dashed line at 50%). Marker shape shows the source type: Raters (triangle), Models (square), Markets (diamond) and, on race charts, Polls (circle). On the chamber control charts, higher up means a smaller historical error (√Brier) in our 2018–24 backtest (ANALYST); sources with no track record yet sit in the separate bottom strip. On race charts, larger, more opaque markers have a better track record. Hollow markers have no track record yet or were excluded.
Catalyst forecast: the bold orange vertical line with its value tag. Catalyst 80% range: the shaded orange band behind everything. Model-uncertainty band: the hatched band, showing how the call moves across reasonable modelling choices.
Source's own uncertainty: thick solid bar in the marker's colour (MOE, bid/ask spread or rating crosswalk). Historical accuracy (2018–24): thin dashed grey line with end caps, showing how far that kind of source has typically missed. Hover or tap a marker to highlight its bars and see the source, label and link.
Catalyst v2 forecast (comparison)
Polls + fundamentals blended with stacked forecasters, 50,000 correlated simulations.