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Topics: PMO, Schedule Management
WBS Planning & Management

Good day

First time posting here. I have a question regarding the Planning the Project WBS and its management.

From my understanding and the 8/80 rule that activities should be decomposed to within activities completed between 8 hours - 80 hours. Based on the activities of my projects, this may not be applicable and individual exceptions can be made for them of course.

However, on a general note that the size of the WBS in this project is large (down to six levels and beyond), involving multiple stages with intricate relationships with non-repetitive activities. These also include many duration beyond the 8-80 rule.

Decomposition of WBS for this project following the guideline will lead it to an extremely exhaustive list of activities, making it complicated and difficult to track and manage for a single manager.

As such, I am curious to fellow managers, at what level of depth do you consider for further decomposition to be counter intuitive and ineffective? How do you manage the WBS from spiraling out of management control?

Thanks in advance.
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WBS do not contain activities. That is the first thing to take into account. About a general rule of decomposition the deep of something could be 7+-2 levels.

Dividing complex projects to simpler and manageable tasks is the process identified as Work Breakdown Structure (WBS).

WBS is not restricted to a specific field when it comes to application. This methodology can be used for any type of project management.

In the process of breaking down the tasks, one can break them down into different levels of detail. One can detail a high-level task into ten sub-tasks while another can detail the same high-level task into 20 sub-tasks.
Therefore, there is no hard and fast rule on how you should breakdown a task in WBS. Rather, the level of breakdown is a matter of the project type and the management style followed for the project.

There are a few "rules" used for determining the smallest task chunk.
1- In "two weeks" rule, nothing is broken down smaller than two weeks’ worth of work. It means the smallest task of the WBS is at least two-week long.

2- 8/80 is another rule used when creating a WBS. This rule implies that no task should be smaller than 8 hours of work and should not be larger than 80 hours of work.

3-The another rule is the "if it makes sense" rule. Applying this rule, one can apply "common sense" when creating the duration of a single activity or group of activities necessary to produce a deliverable defined by the WBS.

You may need to refer to PMI's WBS Practice Standard. Some of your perceptions are not true.

What is the key purpose of the WBS?
- to communicate to stakeholders how the scope will be run
- to identify main chunks of work for further analysis and planning

Working extensively with very large WBS, most "rules" are not always applicable beyond "if it makes sense". Even at the 9th level, there may be activities far larger than 80 hours.

As Sergio pointed out, the WBS is not the work. It is how the work is organized. When managing a project with a very large WBS, there are often multiple PMs involved at various levels when there is actually work assigned broadly throughout the WBS. In other cases, a product/program might have a very large WBS but not all branches are involved in all projects, and fewer PMs are necessary.

In very large projects, there might be a PM team at the overarching integration level, at each major functional level, and also at contributing team levels. They are managed and tracked differently according to the who is looking at the project. The program level tracking tools could be looking down to WBS level 6. The detailed level statement of work could be written to WBS level 9. An individual team could decompose a WBS level 9 SOW into a detailed project plan integrating supplier contributions who have their own WBS and project plan.

In general, the WBS should be broken down to the level you need to manage, similar to how a program level schedule has less detail than a functional level schedule or team level working schedule. With multiple layers a PM needs to ensure that the breakdown at their level supports the level above, and that the level below has enough detail to show whether those sub-tiers have a well defined plan and are performing to plan. It is not a one-size-fits-all solution, and we often spend quite a bit of effort arguing over what level of detail is needed vs. adding unnecessary overhead and complexity. If a team has only a 40 hr SOW at level 6, that is all I need. If they have a 1000 hr SOW at level 9, I need to ensure they have a detailed plan beyond level 9, but managed at the group level rather than extending the program level WBS another 6+ levels.

Thank you everyone for your information. Gladly appreciated.

WBS should depict how you want the work to be done. Break it down into small chunks so that you can manage better.

Like Thomas has mentioned above, it is required to communicate to the customer how you are managing the scope

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