The process of decomposing the project scope begins with the high-level project deliverables: such as the project management deliverables, the foundation, the framing, and so. Then each top tier deliverable is decomposed again and again until you've reached the smallest level of deliverables – the work packages. Here's a tip: you know that you have decomposed the project deliverables deep enough by using the 8/80 Rule. The 8/80 Rule means that each work package can be completed with not less than 8 hours of labor and not more than 80 hours of labor.
Just as each project scope statement is unique so too must each WBS be unique. Having said that, it is acceptable to use a WBS from a previous similar project and adapt it to your current project as a WBS template. Some organizations have a consistent level of deliverables with all of their projects so they use a pre-populated template to reflect these "every project" deliverables. For example, you might create a template that reflects your project management plans, quality control charts, and expected reports that the project will generate.
The numbering system is known as a code of accounts. Each WBS deliverable is identified and can be tracked by time, cost, and other metrics using the code of accounts. The code of accounts can also help facilitate communication between the project manager and the project team. Imagine trying to identify which bedroom a contract is discussing in a four-bedroom home construction project. The WBS code of accounts can point all parties to the exact deliverable using the numbering system for each component.
I'll add that the 8/80 rule can have valid exceptions, such as in the case of analytical, support, or project management elements. In these cases there are intangible service deliverables or LOE (level of effort) that may break the 8/80 rule in a valid manner.
Josh Nankivel
WBS training instructor
http://WBSCoach.com
Posted by: twitter.com/pmstudent | January 04, 2010 at 10:15 AM