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An Intro To The Precedence Diagramming Method (PDM)

Peter Landau
Publication date:
September 16, 2022
Article Summary: 

An Intro To The Precedence Diagramming Method (PDM)

The precedence diagramming method (PDM) is a project planning technique that allows project managers to map out all the tasks in a project to plan the order in which they will be executed. It is similar to the program evaluation and review technique (PERT), activity-on-node diagramming and the critical path method (CPM), but each has its key differences. Precedence diagrams are project network diagrams that show tasks, their duration and dependencies. The four types of task dependencies commonly used in task management are also called precedence relationships or PDM relationships. A precedence diagram is a great tool to more accurately develop the project schedule, keep the work on track and automate tasks.
The precedence diagramming method is an important tool for project planning and scheduling. It exposes task dependencies in the schedule, which helps prevent bottlenecks later in the project. To draw a precedence diagram, it is important to gather tasks, list them and identify preceding tasks. It is also important to analyze them all and identify potential task dependencies. Finally, it is necessary to lay out each task or activity as a node represented by a box.

Nodes can include float or slack time, earliest start time, earliest finish time, latest start time, and latest finish time. Different types of project network diagrams are used to assist with scheduling. The Arrow Diagramming Method (AOA Diagram) and Project Network Diagram (AON Diagram) are two diagramming methods used to show the order in which activities in a project are done. The Gantt Chart is a bar chart used in project scheduling, and the PERT chart is used in conjunction with the critical path method to analyze tasks in a project. ProjectManager is project management software that helps users create dependencies, find the critical path and execute their project schedule with ease.


precedence diagramming, project planning, project management, task dependency, program evaluation and review technique (PERT), critical path method (CPM), activity-on-node diagramming, precedence relationship

Source Citation: 
Peter Landau
An Intro To The Precedence Diagramming Method (PDM)
September 16, 2022
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