In earlier articles I have gone through the steps to define the project scope using a Scope Statement. The Project Scope Statement contains the definition of the scope in detail and for IT projects this is typically in the form of an Enterprise Design Document (EDD).
So we have a detailed description of the scope (the design of the software); where do we go from here? We need to break down the project deliverables into progressively smaller components so they are easier to estimate for time and cost. This is also called decomposition and the resulting structure is called Work Breakdown Structure or simply WBS.
In the WBS, the top layer is of general nature and each subsequent layer gets more and more specific until we are left with small units (or packages) that easily can be estimated for time and cost and at the same time provides enough information to proceed with subsequent activities.
At the bottom of the Work Breakdown Structure are nodes or so-called WBS packages (work packages). So when does a node become a work package? Here are some pointers:
The resulting WBS is a graphical and hierarchical chart where each node has a number to uniquely identify it. If you are using Microsoft Project or other project tools the WBS is also often shown as a so-called Gantt chart where each indention is a step down in the hierarchy until we reach the final work package.
Once the WBS chart has been established we need to document the content of each package. For that purpose we must create the WBS Dictionary. The dictionary includes a detailed description of each node and can also include whom it is assigned to, dates, cost, etc.
So what makes a good Work Breakdown Structure? Here are some pointers: