Decision tree pruning

Decision tree pruning reduces the risk of overfitting by removing overgrown subtrees that do not improve the expected accuracy on new data.

Note: This feature is available starting from Db2® version 11.5.4.

Whereas you might prevent the growing of these subtrees by specifying aggressive stopping criteria, a separate pruning process is more reliable.

Decision tree pruning uses a decision tree and a separate data set as input and produces a pruned version that ideally reduces the risk of overfitting. You can split a unique data set into a growing data set and a pruning data set. These data sets are used respectively for growing and pruning a decision tree.