From WBS to Project Network Diagram
The WBS contains all of the activities necessary to complete the project, but it is not a scheduling tool. The project network diagram is a scheduling tool that shows the predecessor and successor relationships between activities from the WBS.
One difference between a project network diagram and a WBS is that a project network diagram contains start and finish nodes. Nodes are essential because they provide anchors for the software algorithms for team members who use software packages such as Microsoft Project.
When you combine all of the products and activities from the WBS, the project network diagram, estimates, and resource requirements, you will have a clear road map of the what, when, how, and who of the project.
To create a project network diagram, list the activities or tasks for the project. These become the activity nodes in your project network diagram. Ask the project team if they have activities that need to be finished before other activities can start. Record the order in which activities need to be completed. Working in this way, continue identifying and then drawing the dependency relationships to create a network diagram of the project.
Remember that a project network diagram is built only from the level or levels in the WBS in which work is assigned and accomplished. WBS activities are represented as a sequence flowing from left to right on the diagram. An arrow going into the left side of a node indicates the start of a task. An arrow leaving the right side of the node indicates the end of a task.