Precedence Diagram Method

The Precedence Diagram Method (PDM) is a visual representation technique that helps in depicting the activities involved in a project. PDM was developed after the PERT/CPM techniques. The function of PDM is to permit a more accurate depiction of relationships among various activities. Following are the types of dependencies to be taken care of before creating a Precedence Diagram

1. Finish-Start: An activity cannot start before a previous activity has ended in this dependency. This is the most commonly used dependency.
2. Start-Start: There is a defined relationship between the start of activities, in this dependency,.
3. Finish-Finish:, There is a defined relationship between the end dates of activities, in this dependency.
4. Start-Finish: There is a defined relationship between the start of one activity and the end date of a successor activity, in this dependency. This dependency is rarely used.

A manager is provided with various network scheduling techniques that acts as a powerful tool for scheduling and controlling their programs/projects. Usually, these network diagrams helps in portraying project activities and relationships among the activities graphically. This graphical representation helps to determine the project’s critical path, predicting shortages, and identifying possible reallocation of resources find a suitable solution.

Nowadays there are readily available software which assists in accordingly finding network schedules that are easy to update and rework, thus providing managers with current program/project status information and control over activities and schedules.

Precedence diagram method (PDM) is a mainly 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.

PDM helps to find,

1. Critical tasks, noncritical tasks, and slack time
2. Shows the relationship of the tasks to each other
3. Allows for what-if, worst-case, best-case and most likely scenario