About the Work Breakdown Structure

A Work Breakdown Structure (WBS) is a hierarchy of tasks and subtasks required to complete a project. A WBS task is work assigned to a project member by a Project Lead. This is where you create the project structure, define due dates for tasks, and assign people to complete the tasks. Tasks are associated with a project, but have their own lifecycle.

The topics in this section focus primarily on the WBS for a project. The WBS for a project concept is very similar and almost all instructions and points apply to project concept. For the few differences between the WBS for projects and project concepts, see About Project Concepts. There are more differences for a WBS in a project template. Generally, the project template WBS contains no information related to dates or the % completion for a task, including metrics and status indicators. For a complete list of differences between the WBS for projects and project templates, see About Project Templates.

Related Topics
About Projects
About Tasks

Task ID

The WBS of a project maintains constant task IDs:


  • When the first task is created, the sequence number of that task will be 1. This sequence number will be incremented by 1 for next task that is created.
  • When a task is inserted into the WBS of the master project schedule, the task ID of the task will be the incremented value of the immediately preceding task. The remaining WBS tasks, after the level in which the task was inserted, will be re-sequenced accordingly.
  • When a task is added in the end of the WBS of the master project schedule, the task ID of the task will be the incremented value of the immediately preceding task. The remaining WBS tasks will be not re-sequenced.

For example, consider the following WBS structure:

Task Name

Task ID

T1

1

---T1.1

2

T3

3

T4

4

If a new task T1.2 is added as a subtask to the task T1 by selecting the Task T1.1 and clicking the "Insert Task Above" command in the structure browser, then the WBS will be re-sequenced as follows:

Task Name

Task ID

T1

1

---T1.2

2

---T1.1

3

T3

4

T4

5

If a new task T1.3 is added in as a subtask to the task T1 by selecting Task T1 and clicking "Add Subtask" command in the structure browser, then the WBS will be re-sequenced as shown below:

Task Name

Task ID

T1

1

---T1.2

2

---T1.1

3

---T1.3

4

T3

5

T4

6

If a new task T5 is added to the end of the WBS structure as shown below, then the WBS structure will not be re-sequenced.

Task Name

Task ID

T1

1

---T1.2

2

---T1.1

3

---T1.3

4

T3

5

T4

6

T5

7

  • When an existing project is added to master project schedule, the added project will be assigned a subsequent constant task ID based on the position into which it is inserted in the master WBS.
  • The existing WBS will be re-sequenced if the project is not added at the end of the master project schedule. This assignment of the Task ID to the added project will not affect the tasks which are present in the added project.
  • When the added project is expanded, the task under that project will have its individual sequence numbers starting from 1.

For example consider project P1 and project P2 with the following WBS.

WBS of Project P1

Task Name

Task ID

P1

  

--T1

1

--T2

2

WBS of Project P2

Task Name

Task ID

P2

  

--A1

1

--A2

2

If we add project P2 into the WBS of project P1, by selecting the task T1 and clicking on the "Copy WBS To Selected Task" command, the WBS of project P1 will be displayed as follows.

WBS of Project P1

Task Name

Task ID

P1

  

--T1

1

-----P2

2

--T2

3

If we expand the project P2, the WBS of the project will be as follows:

WBS of Project P1

Task Name

Task ID

P1

  

--T1

1

-----P2

2

-------A1

1

-------A2

2

--T2

3

Critical Path

Critical tasks in Program Central are identified in red. These are tasks with no room to slip on the critical path. The critical path of the project is the sequence of tasks from beginning to end that takes the longest time. No task on the critical path can take more time without affecting the end date of the project. In other words, none of the tasks on the critical path has any slack.

Following are some considerations about the critical path:


  • In a project with two tasks, and no dependencies, the critical path is the one with the longest time to finish. If both tasks have the same number of days to finish, both are critical tasks.
  • The critical path can change from one series of tasks to another over time as tasks are completed and as tasks in another series of tasks are delayed. However, there is always one overall critical path for any project schedule.
  • Because the WBS schedule is only calculated based on estimate start and end dates, the critical path is updated only if the estimated start and end dates of WBS task are modified.
  • Any task on the critical path is a critical task since it must be completed for the project to finish on schedule. The task start date, duration, and task dependencies can affect whether a task becomes critical.
  • The Master Project will have multiple critical paths when it has related projects in the WBS. Every related project in turn will have its own individual critical path, which is independent of the Master Project's critical path. This feature enables the related projects to maintain their own critical path even when they are added to the master project schedule. For example, if there are two related projects, say RP1 and RP2, in a master project schedule P1, then the RP1 related project will maintain its own critical path and RP2 will have its own critical path. Thus, a consistency of the related projects can be maintained, across all the projects in which it is inserted as a related project. This consistency is needed because the same related project can be inserted in multiple Master schedules.

About Exporting WBS Data

Project members can export project and WBS information. This export file is formatted according to the import file format requirements (see About Project Importing), so after editing the information in another application, you can import it back into ENOVIA Program Central. For instructions, see Exporting a Project.

You can also export the data displayed on the Work Breakdown Structure page, both the WBS view and Baseline view.