Regularization reduces overfitting by discouraging overly complex models.
| Technique | What it does | When useful |
|---|---|---|
| L2 (Ridge) | Shrinks weights smoothly | General stabilization |
| L1 (Lasso) | Pushes some weights to zero | Feature selection |
| Dropout | Randomly drops neurons during training | Deep networks |
| Early stopping | Stops when validation stops improving | Prevents late overfitting |
| Data augmentation | Adds transformed samples | Vision/audio tasks |