Backtest performance

Each completed game is predicted before its result updates the team ratings. The current configuration is selected by a simple walk-forward grid search on recent completed games.

Scored 3,468 games from 3/18/2025 to 6/9/2026.

Brier
0.245
Accuracy
55.6%
Log loss
0.683
Home wins
53.8%

Out-of-sample backtest

Walk-forward result over 3,468 scored games. Lower Brier is better.

Model Brier
0.2448
Baseline Brier
0.2486
Accuracy
55.6%
Skill vs baseline
1.5%

Baseline = constant home-win base rate. Generated 6/9/2026.

Calibration by probability bucket

Bucket
Avg pred
Observed
Games
30–40%
36.5%
33.1%
127
40–50%
46.2%
48.9%
883
50–60%
54.8%
54.6%
1796
60–70%
63.2%
60.8%
613
70–80%
72.1%
79.6%
49

Model configuration

K-factor
12
Home-field Elo
35
Temperature
1.4
Season carryover
0.85