APPROPRIATE LEVEL OF DETAIL

How much detail should be included in the WBS? There is no single answer other than “it depends.” Generally, the part of the WBS that focuses on the product breaks down to a lower level than the cross-cutting elements. Because the lowest level of the WBS is the work package, the answer to the level of detail depends on the appropriate level for the work packages.

There is an important consideration about the amount of knowledge currently available about the project when preparing the WBS. For a large project, there may not be enough detail known to structure the WBS to a level appropriate for planning and scheduling, especially when a “rolling wave” concept of planning is being used. Each level of the WBS must meet the 100 percent rule so that all the work is accounted for; it is just not yet decomposed.

Looking at Figure 2-13, it is clear that the work packages need to be at Level 3 or below because more than one functional organization would be expected to be involved in each Level 3 item. Similarly in Figure 2-14, the work packages are identified as the lowest level (in bold) WBS elements. The activities are at the next level. If you use only the criterion that each work package has only one organizational entity responsible, then the level of decomposition tends to take care of itself, especially when the responsible person/organization is a first-level supervisor.

In general, the lowest level should allow for a reasonable definition of tasks or activities using the methodology presented in the next section. The activities should not be so detailed that they become a burden to plan, schedule, and track, nor should they be so broad that responsibility cannot be identified and progress cannot be measured often enough to maintain control of the project. It is recognized that the preceding statement is not much practical assistance, but with a little experience, the appropriate level of detail for a given organizational culture is readily determined.

A further consideration is the type of work package. Those that contain work that is essentially “level-of-effort” do not need to have much detail. These types arise in EVMSs, where it is necessary to account for all resources or dollars. A typical level-of-effort activity is the work of the project manager and any secretarial or administrative support. They may be assigned to a single work package (or activity) that is scheduled to span the duration of the project.

FIGURE 2-14 Example of WBS Elements and Activities