Subtrees, Use in Constructing Decision Trees

A subtree is a portion of a decision model that is repeated in various places throughout the tree. Since decision models must reflect the real-world complexity of clinical medicine, compact notational representations that highlight repetitive structure throughout the decision model significantly improve comprehensibility. Much like a subroutine in common computer programming languages, the decision tree fragments represented by common subtrees are homologous structures that can be shared by many decision strategies and events.

Subtrees are a powerful notational representation and cognitive tool that can simplify and compact the decision tree representation graphically, emphasize analogies among events shared by multiple paths in the tree, highlight relations among factors in a decision model (e.g., through linkages and bindings), and ensure structural symmetry, helping the decision analyst to avoid ...