Activity Network Diagrams; PERT and CPM Analysis
In this section we are going to examine how to create logical flow of work by use of networks of interdependencies. Network diagramming techniques have evolved from different sources over the last 40 years, and the terminology has also evolved. There are two primary formats for Activity Network Diagrams: PDM and ADM. In a PDM diagram, tasks are represented by boxes or circle. In an ADM diagram, tasks are represented by arrows.

Activity on Arrow, or Arrow Diagramming Method (ADM)	Activity on Node, or Precedence Diagramming Method (PDM)