Weight decay is a regularization method that penalizes the squared magnitude of model parameters, discouraging large weights and promoting simpler models. In multilayer perceptrons, apply it to nonbias weights W rather than bias parameters b to help prevent overfitting. section 10.1
Use weight decay as one option within a broader regularization strategy:
- Increase model capacity with additional layers or hidden units when the model underfits. section 10.1
- Prefer weight decay when overfitting calls for smaller weights and simpler models. section 10.1
- Contrast it with early stopping, which halts training as validation loss rises, and dropout, which randomly removes dense connections. section 10.1








