GROWTHLIMIT Subcommand (TREE command)

The GROWTHLIMIT subcommand specifies stopping criteria that limit the size of the tree. Each keyword is followed by an equals sign (=) and the value for that keyword.

Example

TREE risk [o] BY income age creditscore
 /METHOD TYPE=CRT 
 /GROWTHLIMIT MAXDEPTH=4 MINCHILDSIZE=10.

MAXDEPTH Keyword

MAXDEPTH specifies the maximum number of levels of growth beneath the root node. You can change the maximum depth to adjust the size of the tree.

AUTO. Three levels for CHAID and Exhaustive CHAID, five levels for CRT and QUEST. This is the default.

value. User-specified value. The value must be a positive integer.

MINPARENTSIZE Keyword

MINPARENTSIZE specifies the minimum number of cases required to split a node. Nodes with fewer cases are not split. You can use this setting to avoid splitting nodes that have few cases.

  • The size value must be a positive integer. The default is 100.
  • MINPARENTSIZE must be greater than MINCHILDSIZE.

MINCHILDSIZE Keyword

MINCHILDSIZE specifies the minimum number of cases in any child node. A node will not be split if any of the resulting child nodes would have fewer cases than the specified value.

  • The size value must be a positive integer. The default is 50.
  • MINCHILDSIZE must be less than MINPARENTSIZE.

MINIMPROVEMENT Keyword

For CRT, you can use MINIMPROVEMENT to specify the minimum decrease in impurity. The CRT growing method attempts to maximize within-node homogeneity. In other words, a terminal node in which all cases have the same value for the dependent variable is a homogeneous, "pure" node. A node is not split if impurity would decrease less than the specified value.

The improvement value must be positive value. The default is 0.0001. As the value increases, the number of nodes in the tree tends to decrease.