Once we have identified all of the things that we are supposed to produce in the project, it is necessary to develop the specific items of work that must be done to complete all of the work. The work breakdown structure takes the project and divides it into smaller pieces. These can be called subprojects. The subprojects can be broken down into smaller pieces. This process of breaking down the project can continue until the project is broken into small, more manageable pieces.
The work breakdown structure allows us to approach the formidable task of finding all of the work that is necessary for completion of the project. This is done by taking the formidable project and dividing it into small projects that can be looked at one by one, allowing the project to be attacked one piece at a time. When the work breakdown structure is not used, it is very likely that many of the tasks will be missed. Since this is the place in the project where the work is defined, we find the work breakdown structure useful in determining much of the information we will require in our project plans.
To make work breakdown structures even easier, they are not restricted to only dealing with work. Many work breakdown structures start out as product breakdown structures. That is, the first few levels of the WBS are the breakdown of the products of the project from major products into smaller subproducts. For large projects this frequently makes the construction of the WBS much easier. If, for example, you were to consider the construction of the U.S. space shuttle, you would first see a product breakdown followed by a work breakdown.
Some of the major components of the space shuttle program were construction of the launch facility, construction of the space shuttle vehicle, construction of the solid rocket boosters, construction of the external fuel tank, modification of the world tracking stations, modification of the astronaut training facility, development of new space suits, and development and construction of the robot arm assembly.
The space shuttle program had several layers of product breakdown before the WBS considered actual work packages, tasks, and activities. In huge projects like this, the individual products are so large in themselves that there might be little interaction between team members working on widely separated branches of the project. People working on the external fuel tank had relatively little contact with the people working on the tracking stations around the world.
The work breakdown structure is a simple, easy-to-read, graphical representation of the project that is very useful for communicating to the stakeholders of the project.
The work breakdown structure provides us with the basis for performing the bottoms-up cost and schedule estimate for the project as well. Since the WBS represents all of the work that must be done to complete the project, we can estimate the cost and duration for each of these small pieces of work and roll the estimate up to the project level for the total cost and duration estimate.
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The work breakdown structure is one of the most useful tools in project management. It is easy to use and simple to understand. Essentially, the project is first taken as a whole and broken down into a small group of subprojects. These subprojects can each be broken down into subsubprojects. These can be broken down further until very small pieces of the project can be described.
This breaking down of the project has some major advantages. The main advantage is that it allows us to concentrate our efforts on small parts of the project one piece at a time. If we were to try to determine at once all of the work necessary to complete a project, we would probably do a good job in some areas and a not very good job in other areas. By breaking the project into...