In work breakdown structure, how do I represent a common work that is being used by multiple higher-level-work/module? For example, in my development, I have multiple modules in my IT system, and two of them are Customer and Sales Order. These two modules require additional development whereby I need to synchronise the data (replication) to another server. How do I show it in WBS?

I have put up two examples as in the image, but both seems wrong to me. enter image description here


  • Why do you use WBS for this? Data dependency should be shown with possibly other diagrams like process flow/data store diagram or sequence diagram.
    – NoChance
    Nov 11, 2018 at 4:15

4 Answers 4


There isn't a lot of information in your question, so I'm having to make some assumptions, but I think your second diagram is correct.

If the

  • Deliver Customer processing module depends on "develop common library"
  • Deliver Sales Order module depends on "develop common library"

then the answer is fairly simple - define a new work package "Develop common library", and make both of the other modules antecedents/dependents.

If there are two separate applications, then diagram 1 is ok - but if the application is the same, then this diagram will create problems - the diagram should represent all the work to do the task - if the same work is represented twice then the diagram will mis-represent the amount of work to be done.


Either works. "A" looks more logical and would likely be easier for other stakeholders to consume but "B" is fine, too. In "B", your dev task is acting like a hammock activity.

What is most important here is that YOU understand the logic and can manage the work. The whole idea behind a WBS is to break your work down into manageable pieces, the key word being manageable. So use the structure that you can understand, analyze, defend, predict, etc.

I think you had trouble because a work package has the same name. Consider the work being done to overhaul a house. It is likely you would have two different accounts for the kitchen and a bathroom. Both rooms have walls and those walls need to be painted. I will guarantee you in that WBS you would have "paint walls" under both accounts. You'd have others, too: "install fixtures." One might be a dishwasher and the other might be a toilet. Duplicate activities under different accounts is a non issue.


I am not guru of WBS, but I usually put the common works right under Dev node. Or create so-called "Common" node under the Dev node, and put common things under Common.


B is definitely not correct, because Replication has two parent nodes.

I modified your diagram a bit, calling it A'. The assumption here is that the Replication for one module is independent of the other. If it's not, then the diagram doesn't apply.

To complete the Customer module, you must complete Development (I used that term because you refer to "These two modules require additional development... ") and Replication. Those two activities are 100% of the work needed to complete the Customer module.

Updated image of A

Similar logic applies to Sales Order module, which I "left as an exercise for the reader".

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