Model Variables (TREE command)

The command name TREE is followed by the dependent variable, the keyword BY, and one or more independent variables.

Dependent Variable

The dependent (target) variable must be the first specification on the TREE command.

  • Only one dependent variable can be specified.
  • The dependent variable cannot be the WEIGHT variable.

Independent Variables

You can specify one or more independent (predictor) variables.

  • ALL and TO can be used in the independent variable list. ALL represents all variables in the active dataset. TO refers to a range of variables in the active dataset.
  • In general, if the independent variable list refers to the WEIGHT variable or a variable that is used elsewhere in the tree specification (e.g., dependent variable or cell weight variable), the variable is not used as an independent variable. The exception is that scale variables used both in the independent variable list and the INTERVAL subcommand are not dropped from the independent variable list.
  • Repeated instances of the same independent variable are filtered out of the list. For example, a b a c a is equivalent to a b c. Assuming that the active dataset contains variables a, b, and c, a ALL is also equivalent to a b c.