Work breakdown structure
In project management, a work breakdown structure (WBS) is an exhaustive, hierarchical (from general to specific) tree structure of deliverables and tasks that need to be performed to complete a project.
The purpose of a WBS is to identify terminal elements (the actual items to be done in a project). Therefore, WBS serves as the basis for much of project planning.
Work breakdown structure is a very common project management tool. Many United States government statements of work require work breakdown structures.
How to build a WBS
Whether the WBS should be activity-oriented or deliverable-oriented is a subject of much discussion (http://www.maxwideman.com/musings/wbswar.htm). There are also various approaches to building the WBS for a project (see e.g. How to Build a Work Breakdown Structure below). Project management software, when used properly, can be very helpful in developing a WBS, although in early stages of WBS development, plain sticky notes are the best tool (especially in teams).
An example of a work breakdown for painting a room (activity-oriented) is, to state the obvious:
- Prepare materials
- Buy paint
- Buy a ladder
- Buy brushes/rollers
- Buy wallpaper remover
- Prepare room
- Remove old wallpaper
- Remove detachable decorations
- Cover floor with old newspapers
- Cover electrical outlets/switches with tape
- Cover furniture with sheets
- Paint the room
- Clean up the room
- Dispose or store left over paint
- Clean brushes/rollers
- Dispose of old newspapers
- Remove covers
The size of the WBS should generally not exceed 100-200 terminal elements (if more terminal elements seem to be required, use subprojects). The WBS should be up to 3-4 levels deep. Each level should be 5-9 elements broad. These suggestions derive from the following facts:
- short-term memory capacity is limited to 5-9 items.
- having fixed time to plan a project, the more terminal elements you have, the less time there is to pay attention to any single one of them. Consequently, your estimates are less thought-through.
- the more terminal elements you have the more there are potential dependencies among them (see fact 2 above for consequences).
Books
- Carl L. Pritchard. Nuts and Bolts Series 1: How to Build a Work Breakdown Structure. ISBN 1890367125
- Project Management Institute. Project Management Institute Practice Standard for Work Breakdown Structures. ISBN 1880410818
- Gregory T. Haugan. Effective Work Breakdown Structures (The Project Management Essential Library Series). ISBN 1567261353
Links
- US Department of Defence(DoD) Handbook Work Breakdown Structure: MIL-HDBK-881 (http://www.acq.osd.mil/pm/newpolicy/wbs/mil_hdbk_881/mil_hdbk_881.htm)
See also