Lesson 4 of 8
Overfitting and underfitting
In plain words: Overfitting is memorising the training data; underfitting is not learning enough from it.
- Overfitting: training score keeps improving while validation score gets worse.
- Fixes: more data, Data augmentation, simpler model, regularisation, early stopping.
- Underfitting: both training and validation scores are poor.
- Fixes: a more powerful model, better features, train longer.
- Plot training vs validation scores per epoch — the gap tells you which problem you have.
Tip Early stopping (stop when validation stops improving) is the easiest overfitting fix.