The HEIGHT statement specifies the name of a numeric variable to define the height of each node (cluster) in the tree. The height variable can also be specified by the HEIGHT= option in the PROC TREE statement. If both the HEIGHT statement and the HEIGHT= option are omitted, PROC TREE uses the variable _HEIGHT_. If the data set does not contain _HEIGHT_, PROC TREE uses the variable _NCL_. If _NCL_ is not present either, the height of each node is defined to be its path length from the root.