Create Annotated Labels for rpart Trees

Generates custom labels for each node in an rpart classification tree to aid in understanding CART's pruning algorithm

Usage

annotree(
  mod,
  show_classes = TRUE,
  show_gt = FALSE,
  show_cp = FALSE,
  show_pruned = FALSE,
  show_min = FALSE,
  show_leaf_dev = FALSE,
  show_internal_dev = FALSE,
  main = NULL
)

Arguments

mod

an rpart object

show_classes

logical. If TRUE show class labels and counts. Defaults to TRUE.

show_gt

logical. If TRUE the g(t) term (misclassification reduction per split) is included. Defaults to FALSE.

show_cp

logical. If TRUE the complexity parameter (cp) value, calculated as g(t) divided by root node deviance is included. Defaults to FALSE.

show_pruned

logical. If TRUE the nodes slated for pruning are plotted in a distinct color. Defaults to FALSE.

show_min

logical. If TRUE the node with minimum g(t) is labeled "*minimum". Defaults to FALSE.

show_leaf_dev

logical. If TRUE leaves are labeled with "dev" (misclassified cases). Defaults to FALSE.

show_internal_dev

logical. If TRUE internal nodes are labeled with "dev" (misclassified cases). Defaults to FALSE.

main

An optional title for the plot.

Details

This function is primarily used to create informative labels for internal nodes and leaves in classification trees.

• For leaf nodes, it displays the word "leaf" and the node's deviance.

• For internal nodes, it can display the g(t) equation, cp value, and optionally indicate the node with the smallest g(t).

Examples

library(rpart)
kmod <- rpart(Kyphosis ~ Age + Number + Start, data = kyphosis, cp = 0, minsplit = 2)
annotree(kmod)