written by: Amanda Dcosta
• edited by: Linda Richter
• updated: 12/20/2010
The WBS breaks down the entire work of the project into bite-size deliverables. Work that has not been defined in the WBS is outside the scope of the project and can be ignored. A WBS Scope relationship diagram outlines the relationship of required work deliverables in support of the project scope.
When a project is launched to create a new product or service, it ideally should start at some starting point. Just like the engine is turned on to start a car, likewise is a step taken or an action taken to initiate a project. This starting point would be with the project scope or the project scope statement.
The project scope may be defined as 'the total work that is required to execute a project and is the constraining factor within which the project has to perform.' (USA's PMBOK Guide).
The project scope statement justifies the reason or need for the project. It highlights all the stakeholders involved, authorizes the project, informs who the sponsor or sponsors are, and also highlights the main events or activities that the project will go through. It will also outline constraints such as duration and cost.
It highlights two main features, namely:
What the project will deliver on completion; the product or service.
The total work that will have to be done to meet the above-mentioned objective.
Once the scope statement is in place it gives way for the Work Breakdown Structure. An example of a WBS Scope Relationship Diagram is added at the end of this article for ease of understanding.
Now that the project scope is in place and identifies the work that has to be done, this total quantum of work will have to be decomposed. Decomposition, in project management terms, is nothing but breaking down into the least possible 'workable' parts. Breaking down of the total work will begin with the Product Breakdown Structure. In other words, the product is broken down theoretically into smaller components, divisions, or departments. It is from the breaking down of the product that we arrive at the work related to each decomposed product section.
The Work Breakdown Structure, once understood, will highlight work along different levels beginning with the scope of the project (project name) until it has reached the level where it cannot be broken down any further. The lowest level of work that can be done is called a 'work package'. There can be many work packages, where a group of work packages may be linked to a single parent task, a level above it.
By taking a look at a Work Breakdown Structure, one can see the WBS-Scope Relationship. The WBS simply supports the scope by detailing the total quantum of work outlined in the scope. Without the scope statement, it would be difficult to create the Work Breakdown Structure, and without the WBS, it would be difficult for the scope to be understood.
Any work not mentioned in the WBS is outside the scope of the project and is not to be carried out.
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WBS-Scope Relationship Diagram
Take the example mentioned in the image above. The scope of the project is mentioned as "Build a mall to accommodate 20 stores of 20,000 square feet each." From the project name mentioned as the 'scope.' it can be seen that the scope should be clear and concise.
In order to break down this product (Mall) into workable bits, we have to decompose the product into divisions. This gives rise to divisions such as Architect, EPC (Electrical, Plumbing, Construction), IT, Government Involvement, etc. From there on, each division's work can be defined and broken down till it reaches the lowest levels of work packages. The WBS-Scope Relationship Diagram to the right (click to enlarge) illustrates this example.