In AOA and precedence diagramming, the activities are represented by nodes rather than arrows.
PDM Logical Relationship • The left side of the PDM node is designed the “start side” and the right side is designed the “finished side”. • Because of the importance of the side, PDM uses arrowheads to identify the direction of relationship. • Precedence diagramming allows more flexibility in modeling relationship than AOA diagramming. AOA diagramming allow only one kind of logical relationship : a preceding activity must be complete before any succeeding activity can begin. • The four logical relationship used by PDM are : Finish to start, Start to start, Finish to finish, Start to finish
FS Relationship • The most common precedence diagramming relationship. • The succeeding activity cannot start until he preceding activity has been completed. • FS relationship can be expressed in three forms if lag is used, zero lag, positive and negative lag.