Rather than having a single BN ‘consequence’ node with a probability table
determined from the logical relationship between events and consequences, it is
possible to represent this relationship using a hierarchy of nodes, determined from the
event tree structure. A node can be introduced for each vertical line (representing a
branch or decision point) in the event tree provided that more than two sequences lead
from the branch. The parents of this node are the node representing the event and the
nodes from the decision points to the right. Using a hierarchy of nodes has two
potential advantages: