The first step in building a schedule: the WBS

The first thing you need to do when building a project schedule is to create a Work Breakdown Structure (WBS).

The first thing you need to do when building a project schedule is to create a Work Breakdown Structure (WBS). Creating a WBS allows you to look at the project at a high level and then break it into smaller pieces until you can get the full picture of the totality of work that needs to be performed. The project manager may be able to create a draft of the WBS as a starting point or the entire team (and clients) can create a WBS in a group exercise.

The general process for creating a WBS is as follows:

  • State the name of the entire work effort. This is the top level of your WBS (generally called level 0.0)
  • Look at the large chunk of work and break it down into smaller pieces that together represent the larger chunk. You might break a large piece of work into two smaller parts, five smaller parts, or whatever number of smaller parts makes sense. Sequencing is not important at this time.
  • After you finish your work breakdown, do a quick estimate of the effort required to complete each individual work component to see if the work effort is larger than the "estimating threshold." This estimating threshold is based on how large you want the final activities to be. It's easier to manage four forty-hour activities than one 160-hour activity. For a typical business project, we recommend that you try to break the work into activities that are no larger than 80 hours of effort, but this number could be higher or lower based on the size of your project.
    You should also look at each chunk of work to determine whether it's simple enough that you understand it. This is important because the work at the lowest levels of the WBS (work that is not broken down any further) will be moved to the schedule. If you have work on the schedule that's vague and not understandable, you won't be able to assign the work to a team member for completion.
  • Look at each of the work components that you have broken down from the higher level and apply the two checks from step 3. If either of the answers is "no" then you would repeat steps 2 and 3.

The process of breaking the work components into their lower level set of activities (steps 2-3 above) should continue until all work components are represented as granularly as necessary, with no activities having estimated effort larger than the estimating threshold and where you understand all of the work. This is when the WBS is complete.

There is a caveat to the work breakdown process above. If your project is very large, it's also likely that you may not know enough to be able to break all of the work down to the level described above. This may still be okay as long as those higher-level chunks of work are far in the future. In this case, you can leave the work at the higher level until you get closer to executing the work. When this higher level work is within three months of executing, you should know enough to be able to break the work down at a more granular level.