What is the main use of the WBS?

There is a discussion going on on Facebook about WBS and what would be the use of the WBS. Like many PMP questions, the real world answer might be slightly different than the PMP exam.

Here is the question posted without editing.

What is WBS used for :
1- only for complex project
2-used for planing
3-top to down list of activities
4–down to top itemes of project

This link is to a video on PBS and WBS. The video is not a direct response to the Facebook question, it was recorded a while back.

Back to the question. Answers 1 and 4 cannot be right; will not get into reasons here. That leave us with 2 or 3 and here is where the real world practice can be different than the PMP exam, as we will explain here.


Per the PMBOK Guide (and the PMP), the definition of the WBS leads us to Answer 2, since the output of the WBS process is used for planning and control. Control is not mentioned here so “for planning” is good enough.

Why Answer 3 is not correct in the exam? Because in the exam, one of the things that make it tricky, is you have to define the process, and its output – by being very specific and in the guide, activities are part of another process in time management.

Now, Real World

In the real world, does it matter if the activities are the output of the Create WBS process (part of scope management) or Define Activities process (part of time management? Is your performance appraisal or effectiveness in managing projects a function of knowing in which knowledge area you perform this task?

In the real world, many planners (scheduling – time management people) are the one developing the WBS, if used at all, and not the scope people. Of course, this is not a general statement since practices vary from one place to another. However, at least in capital projects, planners are the one performing this work and often using their scheduling tool to break down the project into smaller and smaller deliverables down to the work packages AND the activities. If you accept this point, then the answer to this exam question in the real world is 3.

But the PMBOK Guide

Some will argue and debate that the PMBOK Guide is clear and it must be 2. Well,

  1. The PMBOK Guide and PMI are not the original author or developer of the concept of WBS.
  2. The PMBOK Guide does not always reflect real world practice; there are some gaps.

Well, here is ISO 21500. ISO have the Define Activities process in Scope Management and not time management. ISO used the PMBOK Guide as a reference, along with info from IPMA and others. So why is ISO different here? Why define activities is a scope process and not a schedule process? Agree or disagree, this point is to demonstrate that the real world could be different than the PMBOK Guide or ISO and practices may vary from one place to another.

But, the WBS is …

One of the arguments stated that Answer 3 cannot be correct, not even in the real world since the WBS cannot be a list. It is a “hierarchy”, meaning graphical. Is it? When a planner is developing the project schedule, is she always using graphical breakdown? Even if that feature could be available in P6 or MS Project, a graphical representation is not always used.  

How to develop a WBS

Video Related to the SubjectNow, what is the best way to develop a WBS? In our views, the best way is to draw a WBS graphically, using organization chart style or inverted tree. We recommend that every project should have a WBS and more than one. In CAMMP, the WBS & PBS are crucial for defining scope.

However, what is important in the end is the output and how to use the result of the WBS process. The result, per the PMBOK Guide, is the list of deliverables, the work packages; and the dictionary. However, the next step is to convert the work packages to the activities list. In other words, we have two types of outputs (1) work packages list and (2) activities list. In other words, the end result of the technique is to produce lists to use in planning and control, also in communication and other relevant needs.

Closing Comments

I want to close with a question (or more than one).

  • Why do we develop a WBS? Is it for the fun of using a decomposing technique or the output?
  • At the end of the process, is it enough to have work packages or we need to proceed to the activities list?
  • We can only call it a WBS if we use graphical tools like WBS Pro, Mind Mapping, or Org Chart? Or, if we generate a breakdown in Excel or MS Word and create is acceptable?
  • Is the objective the look or the list?

What do you think?