How good is the model?
Calibration over 973 decided games across 2023, 2024, 2025, 2026. Each row groups games by the home win probability that was forecast; a well-calibrated forecaster's "actual" column matches its "forecast" column. Brier score is mean squared error, lower is better.
Elo Brier: 0.2173
Closing spread Brier: 0.2126 over 973 games with a line
Constants: K 20, home field 48, bye +25, playoff ×1.2, offseason reversion 50%, QB multiplier 3.3. Tune them with
scripts/tune.ts.| Forecast bin | Elo games | Forecast | Actual | Δ | Spread games | Forecast | Actual | Δ |
|---|---|---|---|---|---|---|---|---|
| 0%–10% | 0 | 0 | ||||||
| 10%–20% | 11 | 17% | 9% | · | 9 | 16% | 11% | · |
| 20%–30% | 42 | 26% | 33% | +7 | 38 | 26% | 24% | -2 |
| 30%–40% | 108 | 36% | 29% | -7 | 150 | 36% | 27% | -8 |
| 40%–50% | 175 | 45% | 39% | -6 | 191 | 43% | 41% | -2 |
| 50%–60% | 222 | 55% | 51% | -4 | 198 | 57% | 60% | +3 |
| 60%–70% | 199 | 65% | 69% | +4 | 239 | 65% | 70% | +5 |
| 70%–80% | 157 | 75% | 70% | -5 | 97 | 74% | 70% | -4 |
| 80%–90% | 56 | 84% | 95% | +10 | 49 | 84% | 92% | +8 |
| 90%–100% | 3 | 91% | 100% | · | 2 | 91% | 100% | · |
Δ is actual minus forecast in points of probability; a negative Δ in the high bins means overconfidence in favorites. Bins under 20 games show a dot.