The Work Breakdown Structure (WBS), part 2

Since the WBS is a hierarchical structure, it has bottom level parts.  The WBS can be constructed like a table of contents, like so:

WBS Item 1 WBS Item 1.1 WBS Item 1.2 WBS Item 1.3 WBS Item 1.3.1 WBS Item 1.3.2 WBS Item 1.4 WBS Item 2 WBS Item 2.1

The lowest level items (shown above in bold) are called ‘Work Packages’.  The Work Packages are discrete pieces of work to be assigned to someone in the project, perhaps an individual, a business unit, and internal, team, or a contractor.  The key is that there is someone responsible for delivering the Work Package.

WBS’s should be oriented towards the deliverables, not towards the functional groups.

The reason for breaking down the project into smaller work packages is for management and control. 

The smaller a piece of work is, the easier it is to estimate how much time is needed to do the work.  Work packages also facilitate the scheduling of the project. The work packages can be the components mentioned in the master schedule. Work packages can be scheduled individually, and the resulting duration be fed into the master schedule, which only shows the work packages.

It is also easier to estimate the cost of smaller work than bigger work.  To estimate the cost of the project, just estimate the cost of each individual work package and sum them up.

The WBS is often claimed to be the backbone of the project, and some writers have said that project failures can be traced back to faulty WBS’s:

“Component or full-project failures, when they do occur, can often be traced to a poorly developed or non-existent WBS”(Norman, Brotherton, and Fried, "Work Breakdown Structures: The Foundation for Project Management Excellence")