How to I define penalties to make it harder for a predictor to become the primary splitter in the node?
A29: CART supports three “improvement penalties.” The “natural” improvement for a splitter is always computed according to the CART methodology. A penalty may be imposed, however, that causes the improvement to be lessened depending, affecting the penalized splitterĀ“s relative ranking among competitor splits. If the penalty is enough to cause the top competitor to be replaced by a competitor, the tree is changed.