I am using the Decision Tree procedure (TREE command) to build a tree. I noticed that each of the predictors that appears in the tree below the first level appears in only one branch. Is this outcome determined by the algorithm?
Resolving the problem
Predictors are not restricted from appearing in multiple branches of a decision tree, either at the same level or on different levels. In your tree, each predictor below level 1 appeared in only one branch, but this an empirical result specific to that tree.