Work Breakdown Structures (WBS)
Your project’s WBS (Work Breakdown Structure) is comprised of simple boxes and lines. It’s easy to forget that these basic elements, with patience and careful planning, can be combined into a powerful and valuable structure—not unlike a child’s castle made of simple wooden blocks. Case in point: I recently attended a one-on-one meeting with my 6-year old’s primary school teacher. I had brought along my younger 4-year old daughter, so the teacher fetched some blocks for my daughter to play with while we talked.
The teacher said they were “wonderful blocks”, but as I looked into the box, I was distinctly unimpressed. Each block was light brown and exactly the same size (about half the size of a playing card, 1/5 inch (5mm) thick), and I failed to see anything wonderful about them. The teacher, however, produced a catalogue containing photographs of castles, bridges, archways, towers and other complex structures, all built from these simple blocks. The pictures were truly amazing, and the blocks kept my daughter occupied for the next 30 minutes.
As project managers, you have simple boxes and lines with which to create your WBS. They too may seem very basic and uninteresting, but you can use these simple elements to create powerful, useful and very important structures to help manage your projects.
Work Breakdown Structure WBS Guidelines
Just as there are guidelines you should follow to successfully build a castle out of blocks, there are guidelines to follow when constructing your WBS. Here are a few:
| WBS Guidelines | Block Castle Guidelines | |
| 1. Clear direction/definition | Make sure you have successfully completed your project initiation activities before embarking on a detailed WBS. | Have a clear understanding of what it is you’re about to build before you start. Trying to change from a castle to a bridge halfway through will be troublesome. |
| 2. Appropriate level of complexity | Develop the WBS to an appropriate level of detail—one that provides the information you need to control the project, but doesn’t swamp you with data/information. | Building a castle using only 10 blocks might be quick, but it won’t be very useful. Alternatively, trying to build a 10,000 block version of Edinburgh Castle will probably consume more time than you realistically have available. |
| 3. Team work | The content of the WBS should be mostly provided by your project team and key project stakeholders – not by the project manager. | If you recruit your family to build the castle, with your help and direction, they are more likely to appreciate the end result, and less likely to knock it down when you’re not looking. |
| 4. Completeness | The WBS should describe the work of your whole project. And there shouldn’t be anything in the WBS that isn’t part of your project. | Make sure you build all of the castle’s features, as one with only three walls isn’t very effective. And castles generally don’t have swimming pools – so don’t include one in your castle floor plan. |
| 5. Accuracy | When documenting the detailed boxes (children) underneath a WBS element (parent), the children must completely and exactly describe the same amount of work as the parent, just in more detail.
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Make sure the first floor of your castle is complete and well-aligned – otherwise it will not support the blocks that comes later, and you’ll be left with all your floors combined into one. |
So Remember
- Just because the elements of a WBS are simple, it doesn’t mean the result isn’t a powerful structure.
- Constructing a WBS that will effectively stand the test of time requires some preparation, patience and a few basic rules – just like a block castle.
- Download a copy of our WBS Checklist.
This article by Kevin Archbold was originally published in PMI’s Community Post newsletter, which is no longer available online.
George,
That is an excellent question, and there is not a one-size-fits-all answer. Many of the questions in the WBS checklist (linked at the bottom of the article above) are aimed at checking to see if you have achieved a sufficient level of detail.
However, in general I have found an easy rule of thumb is that the lowest level task/work packages that end up in the schedule should be about a reporting cycle long. In other words, if the schedule is being updated weekly (and most projects should probably do at least weekly updates) tasks should at a level of 2 days to 2 weeks. If the schedule is being updated every other day, then tasks should be, order of magnitude, about 2 days i.e. anything from 1/2 day to no more than 4 days.
Kevin
Good Article indeed. What do you think is the appropriate level of detail for the WBS. I am quite interested , because I have often seen the issue of not being able to give a %complete figure due to an insufficient decomposition of tasks.