What Is A WBS?

Filed under Definitions, Scope | Posted by PMStudent

Great question from Bill today about what a WBS is and how it’s used in planning project scope:

Hello Josh

Please clarify something for me. I am only into chapter 7 of WBS Coach so if it is explained later please forgive me.

From what I have read so far it seems that the WBS is something different from the schedule. Is that a point you are making or am I understanding it wrong? I thought the schedule was based/ built on the WBS.


You are correct Bill

The WBS is distinct from the schedule.

Specifically, you want to only focus on deliverables when creating the WBS, irrespective of time in my opinion (I still shy away from recommending phase-based deliverables in general, but recognize with some programs that may be the structure used) . ?I also recommend not using staff roles to structure your work breakdown structure.

Then you break those deliverables down into tasks, and the tasks are when then end up on your schedule. Most of the time, your schedule ends up being structured at least in part by the WBS structure, but not always and not completely.

In the PRINCE2 world, they call my version of a WBS a Product Breakdown Structure (PBS). And when I’m talking about task decomposition in a Basis of Estimate (BOE), they do the same thing with what they call a WBS. We’re doing the same things really, but the terminology can make it confusing if you are trying to translate across the pond.

This is why I advise to never even open a scheduling tool until you have first

  1. identified and decomposed all project deliverables on a PBS/WBS
  2. identified the tasks and resources required to create the deliverables

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