How a project manager can create an effective work breakdown structure (WBS)

block of chocolate

A Project is like a block of Chocolate …. best to break it down rather than swallow whole!

What is a Work Breakdown Structure?

The Work Breakdown Structure (WBS) is the way in which a project is divided into manageable tasks by the project manager. A complex project is best tackled by considering the whole project in terms of a number of smaller, less complicated steps toward completion. Doing this before commencement of the project also enables the project manager to accurately identify the scope of the project, as well as assign responsibilities and control accordingly. Finally, the WBS is an aid toward accurate assessment of costs and time of project completion.

Common Mistakes that a project manager make when developing a WBS

Though the work breakdown structure is used to both identify the work required and to assign work responsibilities (to individuals or teams), there are a number of mistakes which a project manager may make when developing the WBS.

The first of these is to make the WBS too detailed in its nature. The project manager who makes this mistake will become a micro-manager of each task. However, the project manager who writes a WBS lacking in any detail will find the project nearly impossible to manage. The exact level of detail required is a balancing act which becomes easier with experience.

It should also be remembered by the project manager that the work breakdown structure is not a project plan, but simply a visual explanation of deliverables. How these deliverables are completed can change through the project (though not without a change request).

Finally, the WBS does not lineate a chain of command, or lines of communication, but is restricted to showing the project deliverables broken down into easily digested chunks.

Creating a WBS

A project manager may use a WBS template to create a hierarchy of work. Within this hierarchy, each level will provide more detail that the previous one. The project manager will require a number of inputs in order to produce the work breakdown structure. These will include:

  • Business Case
  • Feasibility Study
  • Expected Milestones
  • Planned or given Budget
  • The project scope document
  • The “Draft” project management plan

It is important for the project manager to include all stakeholders and team members when developing the WBS, in order to discuss the deliverables and define the levels required under the WBS.

These deliverables are then broken down into smaller chunks under a process known as decomposition. This process allows work to be packaged into pieces that are directly managed by the project manager, and then broken down further to work packages assigned to individuals. Commonly these work packages are produced using the 8/80 rule – no work package is less than eight hours in duration or more than eighty.

How the WBS works for the project manager

The project manager is better able to control a project with the aid of a work breakdown structure, with levels of project deliverables divided into levels as follows:

  • Project
  • Activities
  • Tasks
  • Work packages

Without the benefit of a WBS, delegation of activities and duties to specific stakeholders would become confused. This confusion adds even greater complexity to an already complex project, and estimates of costs, required resource, and time needed to complete the project would become blurred at best. Finally, the WBS performs an important yardstick for measurement of progress against that which has been planned.