NBA holdout results
Logistic regression · Selected on validation log loss before the holdout was scored.
Compare all models and data splits 4 evaluated
Every evaluated model. The same later games.
All candidates use the same data splits and outcome definition. The deployed model is selected by the lowest log loss on the earlier selection block; holdout scores do not decide the winner.
| Model | Selection block | Holdout test | |||
|---|---|---|---|---|---|
| Log loss ↓ | Winner AUC ↑ | Accuracy ↑ | Log loss ↓ | Brier ↓ | |
| Logistic regressionDeployed | 0.6194 | 0.7161 | 67.7% | 0.6172 | 0.4263 |
| Histogram gradient boosting | 0.6286 | 0.6991 | 65.2% | 0.6231 | 0.4337 |
| Extra trees | 0.6231 | 0.7155 | 67.0% | 0.6150 | 0.4258 |
| Training-frequency baselineBenchmark | 0.6894 | 0.5000 | 55.4% | 0.6874 | 0.4942 |
The training-frequency baseline assigns identical probabilities to every game. It is a statistical benchmark, not bookmaker odds. AUC evaluates non-tied games; accuracy, log loss and summed three-outcome Brier use the full holdout.
Earlier data builds the model. Later data tests it.
- 1 · Training6,613 games
- 2 · Calibration1,080 games
- 3 · Selection1,690 games
- 4 · Holdout test1,458 games