Creating a Precedence Diagram
Three common methods of creating project network diagrams are the precedence diagram method (PDM), the project evaluation and review technique (PERT), and the critical path method (CPM).
Many project managers use the PDM to create a specific type of project network diagram. In a PDM diagram:
Although a precedence diagram has specific information, such as predecessor, successor, and duration, written on each box, it is different from a conventional flow diagram. It cannot, for example, contain loops, because this would require moving backward in time.
Each box in a precedence diagram represents an activity at the WBS work element level; these boxes are called nodes. Nodes are linked by arrows that show the nature of the relationship between predecessor and successor activities.