Project Schedule Network Diagrams

Posted on June 24, 2009 by


A Project Schedule Network Diagram is any display of the relationships among project activities which is then used to develop the project schedule. A subnetwork is simply a section of the overall Project Schedule Network Diagram. Project Schedule Network Diagrams are an output of the fourth edition PMBOK®’s Sequence Activities process and an input to the Develop Schedule process. The most common type of network diagram is the Precedence Diagramming Method (PDM) which is also called Activity on the Node (AON). In this diagram, activities are represented by boxes or nodes with arrows connecting these nodes to demonstrate the relationships among activities. The PDM method uses all four types of dependencies between activities (Finish-to-Start, Finish-to-Finish, Start-to-Start, and Start-to-Finish). The older network diagramming method of Activity on the Arrow (AOA) places the activities on the arrows rather than the nodes, and only uses the Finish-to-Start dependency. This method is not as commonly used. Also see the earlier postings of Activity Dependencies (posted June 17, 2009), Sequence Activities Process (posted March 5, 2009), and Develop Schedule Process (posted March 10, 2009).