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Wednesday, July 21, 2004

What is a Work Breakdown Structure?

A Work Breakdown Structure (WBS) is a deliverable-oriented grouping of project elements that organizes and defines the total scope of the project work: work not in the WBS is outside the scope of the project. 

The WBS is often used to develop or confirm a common understanding of project scope.  Each descending level represents and increasingly detailed description of the project elements.  What does the WBS look like?  Work Breakdown Structures s are communicated and organized in many ways. 

The two most common ways to communicate a WBS is either a hierarchy diagram or a table of contents (TOC) layout.  In some cases both formats are used to gain understanding and define the work to be performed.  Typically, complex projects with a large number of internal and external stakeholders respond better to a hierarchy diagram. 

However, to understand and accomplish the specific work tasks, the project team responds better to the TOC layout.

To view more information about a WBS and see an example of a WBS click here

Common approaches to Developing the WBS

The two most common approaches to developing the WBS are the top down approach and the bottom up approach.  Some find a combination of both beneficial.

Top-Down Approach

The top down approach uses a predefined product development lifecycle, or a WBS template, or a WBS from a previous similar project as structured models to define the WBS from general to specific.  This approach involves using a model and reviewing the major project deliverables which have been subdivided into smaller, more manageable components until the deliverables are defined in sufficient detail to support future project phases (planning, executing, controlling, and closing).  

Bottom-up Approach

The bottom up approach uses a planning group to brainstorm the work elements that are needed to deliver the major deliverables of the project.  A planner then groups the output from the brainstorming sessions into phases, activities and tasks.   The bottom up approach involves using a small group of people (5-6) who have some subject matter expertise to plan the project. 

The technique uses the brainstorming method to identify the work needing to be performed to deliver a specific thing.  When the project is large or complex, the brainstorming activity is focused on a major deliverable or end product instead of the broader scope of the project.   The results of the brainstorming session, generally are the pieces of work or tasks that the group knows needs to be done.  It is similar to creating a “to-do list”.  One of the planners then takes this information and groups the related work. These groups may then be grouped again to build up to the highest level of definitions.  The information is reviewed with the original group and they modify, fix, and add any missing pieces. 

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