Validation, Overfitting, Underfitting, Overfitting Underfitting, Machine Learning.
significant loss reduction. In Scikit-learn, a Decision Tree classifier there is a term called ccp_aplha (cost complexity parameter) which is used to do the pruning. At α = 0, there is no pruning. The equation of cost complexity measure is — Here, R(T) is the average impurity of the terminal/leaf