Guide to the Precedence Diagramming Method (PDM)

The Precedence Diagramming Method (PDM) is a fundamental concept in project scheduling techniques as established in the PMBOK Guide Seventh Edition.

Why is it important?
It plays a vital role in depicting the flow of project activities, determining the project duration, identifying the critical path, and profoundly impacts the estimates of time and costs.

What is it?
PDM is a visual representation technique that makes use of nodes to represent the project activities and arrows to show the relationships between these activities. 'Precedence' here refers to the sequential order of tasks.

How does it work?
In a PDM, each activity is represented by a rectangular node, and directional arrows are used to indicate dependencies between activities. There are four types of dependencies in a PDM - Finish to Start (FS), Start to Start (SS), Finish to Finish (FF), and Start to Finish (SF).

Exam Tips: Answering Questions on Precedence Diagramming Method
1. Understand the types of dependencies and be able to identify them in a given PDM.
2. Be familiar with how to calculate early start, early finish, late start, and late finish for each node.
3. Practice PDM problems to get comfortable with identifying the critical path and the overall project timeline.
4. Pay attention to any changes in activity durations or dependencies in the questions, as this may significantly alter the critical path and the outcome of the problem.
Remember, understanding and applying the concept in various scenarios is critical to effectively answering questions about the Precedence Diagramming Method on the exam.