▪ The Work Breakdown Structure is a hierarchy which specifies the list
of tasks involved in a project – down to the finest detail.
▪ The WBS splits the task list up into major ‘packages’
▪ On the following slide, is the WBS for the project to outsource these
▪ The split of the task list into different packages should be logical, and also
compatible with regards to cost control and reporting.
▪ For each Package, it should be possible to test whether the entire package is
completed or not.
▪ You will see 5 different packages in the previous example.
▪ The lowest level of each activity on a WBS should be an individual task
▪ This task should be possible to complete by an individual, or team, within a
reasonable defined period of time.
▪ For example, delegating the task of drawing up action lists could be completed by
an individual within a defined period of time, such as one afternoon.
Limitations to the WBS:
▪ No consideration for the order in which tasks should be carried out, and whether a
task is dependant on another.
▪ No representation of how long each task might take.
▪ Does not show you who, or what resources are involved in each task.
Alternatives to WBS:
1. Product Breakdown Structure
2. Cost Breakdown Structure – Completed AFTER the Work
Breakdown Structure and Product Breakdown Structure
Product Breakdown Structure:
• This is a tool for dealing with complex
products, such as the motorcycle in the
• The PBS provides a means for identifying all
the components that make up a particular
• It is worth noting the Project Management
methodology PRINCE uses the PBS as an
alternative to the WBS.
Cost Breakdown Structure:
• The CBS can only be
completed after the WBS
and PBS (if any). This is
because, for example, the
costs of labour should be
possible to cross reference
with the WBS.
• This is a tool for identifying
each cost category
associated with a project
Sources and Further Reading:
▪ Field, M. and Keller, M. (1998), Croatia: Thomson Learning
– Chapter 2.1
▪ Servello, M. and Evans, M. W. (2002) Work Breakdown Structure.
Encyclopedia of Software Engineering.