WBS
Work Breakdown Structure
DUM 03
Work breakdown structure
• WBS is techique used in project managenet and software engineering
for dividing delivery (or project goals) into individual products.
• It helps to estimate costs and to check upon progress of project
delivery
Decomposition through WBS
• Level of decomposition is not formally defined. Depth of
decomposition may also differ at various parts of WBS
• Aim of decomposition is to define elements small enough so it is
possible to label them with meaningful value. This labeling has to be
done according to the purpose of WBS
• Valuation of WBS elements is done in perspective of time, financial
costs and/or other resources needed for project delivery
WBS example (1)
WBS example (2)
The 100% rule
The 100% rule
• Basic principle of creating WBS. This rules states that WBS has to
always contain 100% of defined goal and cover all deliveries internal,
external and even temporal - from the perspective of work
to be done (work breakdown structure)
• This rule applies to every level of hierarchy. Sum of bottom layer
elements must be 100% of root element of WBS tree. It also means
that it must not contain anything more - it must not make more than
100%.
The rule of mutual exclusivity
• In WBS, no overlap is allowed between two elements in different
branches of WBS tree
• Such ambiguosity would lead into duplicite work or into errors
originating in overlapping of responsibilities during project delivery
• Overlapping might also lead into errors while estimating cost
Common mistakes
• WBS is not an exhausting listing of every activity but a complex
description of project delivery
• WBS is not a project plan, nor project time-table, neither
chronological printout. WBS describes what will be done - it does not
tell how or when
• WBS is not an organisational hierarchy although it might be used for
assigning responsibility