Precedence diagram method

The precedence diagram method (PDM) is a tool for scheduling activities in a project plan. It is a method of constructing a project schedule network diagram that uses boxes, referred to as nodes, to represent activities and connects them with arrows that show the dependencies. It is also called the activity-on-node (AON) method.
 * Critical tasks, noncritical tasks, and slack time
 * Shows the relationship of the tasks to each other
 * Allows for what-if, worst-case, best-case and most likely scenario

Key elements include determining predecessors and defining attributes such as
 * early start date
 * late start date
 * early finish date
 * late finish date
 * duration
 * activity name
 * WBS reference

Slack/Float: Determines the duration of activity delay that the project can tolerate before the project comes in late. The difference between the earliest and the latest start time. i.e. Slack = latest start date - earliest start day or Slack = latest finish time - earliest finish time.

Any activities which have a slack of 0, they are on the critical path.



Different Precedence diagram Methods
 * Arrow diagramming method
 * Project network
 * Critical-path method
 * Gantt chart
 * Program evaluation and review technique