RuleMap compares a
decision tree with a directed acyclic graph (DAG). A strict
decision tree hierarchy allows one parent per
node, while a DAG allows multiple parents per node.
The decision tree is commonly used to document business rules.
When we presented this diagram at ORF2008, we proposed DAGs as an
alternative method for
documenting rules for business users. We also recommended that
Business Rule Engine (BRE) software vendors
incorporate DAGs into their rule engine software to
complement their decision tree functionality. fs
In our experience harvesting
business rules with subject matter experts, DAGs are
just as effective and as easy to understand as decision
trees. For very complex decision trees, a DAG approach helps to
simplify complexity by creating a "slim tree" compared to
strict decision trees.