confidence penalty
**Confidence Penalty** is a **regularization technique that penalizes the model for making overconfident predictions** — adding a penalty term to the loss that discourages the model from outputting predictions with very low entropy (highly concentrated probability distributions).
**Confidence Penalty Formulation**
- **Penalty**: $L = L_{task} - eta H(p)$ where $H(p) = -sum_c p(c) log p(c)$ is the entropy of the predicted distribution.
- **Effect**: Maximizing entropy encourages spreading probability across classes — prevents overconfidence.
- **$eta$ Parameter**: Controls the penalty strength — larger $eta$ = more uniform predictions.
- **Relation**: Equivalent to label smoothing with a uniform target distribution.
**Why It Matters**
- **Calibration**: Overconfident models are poorly calibrated — confidence penalty improves calibration.
- **Exploration**: In active learning and RL, confidence penalty encourages exploration of uncertain regions.
- **Distillation**: Better-calibrated teacher models produce more informative soft labels for distillation.
**Confidence Penalty** is **punishing overconfidence** — explicitly penalizing low-entropy predictions to produce better-calibrated, more honest models.