Surrogate split
Topic of Classification trees, part of Statistical learning
Surrogate split
| Type | Topic |
| Taught in | Classification trees |
| Part | Statistical learning |
A split on another observed variable chosen to mimic the left–right allocation of a node’s primary split. CART uses surrogates to send a case whose primary variable is missing down the tree.
In Classification trees
From Classification trees
Missing-value handling is part of the algorithm and differs between implementations. CART can use surrogate splits: questions on other observed variables chosen to mimic the primary split’s left/right allocation. Sending a case to the majority branch is a fallback, not the definition of a surrogate. In rpart the choices are controlled by usesurrogate and maxsurrogate. State the settings when they affect predictions.
Used in
See also
Decision tree · Node impurity · Building a classification tree · Choosing a split · Invariance to a change of units · Multi-way splits and missing values · Tree size and pruning · What a fitted tree can be trusted to mean