This document discusses work breakdown structures (WBS), which are hierarchical decompositions of the work required to complete a project. It defines a WBS and provides examples. The key purposes of a WBS are to define the project scope, assist with communication and planning, and provide a framework for monitoring progress. The document outlines best practices for constructing a WBS, including ensuring it includes all deliverables and work, decomposing work into an appropriate level of detail, and using a coding scheme. Risks of a poorly constructed WBS include an incomplete project definition and scope creep.

1. Dr Ian Cammack
i.j.Cammack@soton.ac.uk
MSc Project Management
MANG6310: Breakdown Structures

2. Definition
• “A deliverable-orientated hierarchical decomposition of the work to be
executed by the project team to accomplish the project objectives and create
the required deliverables. It organizes and defines the total scope of the
project. Each descending level represents an increasingly detailed definition
of the project work …”
PMI 2006 p. 3

3. Example of WBS

4. Purpose
• Definition of project’s scope / assists communication
• Balances control needs with an appropriate and effective level of detailed
project data
• Framework for specifying performance objectives / estimating & change
control
• Framework for status & progress reports. It supports quest for accountability
• Communication between project manager and stakeholder

5. Key principles
• All the work done by both internal & external participants
• All deliverables - internal, external & interim
• 100% rule:
– the sum of the work at a ‘child’ level must equal 100% of the work
represented by the ‘parent’
– Do not include work outside the scope of approved work

7. • Level 1 is always a single element
• Level 2 high level deliverables / products. Defined by nouns & numbered #.#
(e.g. 1.1)
• Level 3 decomposes level 2 into sub-products or into work processes. Defined
by nouns for products and nouns + verbs for processes. #.#.# (e.g. 1.1.1)
• Level 4 decomposes processes into activities #.#.#.# (e.g. 1.1.1.1)

8. Presentation 1, 2 or 3

9. Presentation 4

10. Presentation 5

11. Presentation 6: WBS Dictionary
Whichever you choose to use make sure it is clear
- font at least 10 pt (A4 page)
- Can be printed out clearly in monochrome (black, grey & white)

12. Project
Deliverables
Product
Elements
Process
Activities
Product
Breakdown
Structure
(PBS)
Work
Breakdown
Structure
(WBS)
WBS Layers

13. Definitions
• Deliverable (Product):an actual entity required by the project; should
be specified within the Statement of Requirements
• Process: a series of actions that produce a change or development
• Activities / Tasks: a specific deed, piece of work required to be done

14. Quality criteria for breakdown structures
• Deliverable orientated grouping
• Defines scope of the work
• Communicates scope to all stakeholders
• 100% of work inc. internal, external and interim deliverables
• Level of decomposition (depth) is driven by risk
• Each element can be assigned to accountable individual / unit
• 100% rule for ‘parent’ : ‘child’ groups
• Nouns for deliverables (upper levels)
• Nouns & Verb descriptors for processes / tasks (lower levels)
• Uses a coding scheme to indicate hierarchical structure
• Create by the people doing the work
• Constructed with technical input from subject experts
• Constructed in an iterative fashion
• Updated in accordance with project change control

15. How Deep Do We Go ?
• 3 or 4 levels should be sufficient BUT it depends on
– Level of risk
– Level of control - what you define you have to control
– Need for estimating accuracy
– Value of the work
– Hours required.
• “Ideal work packages are 80 hours [effort] and less than 2-4 weeks duration”
(Kerzner 1998 p.548)

16. Contractors WBS
Bid packages
•Contractors develop WBS aligned
to owners WBS
•Integrate many subcontractors
WBS into master plan
•Owner tracks against contractors
WBS

17. Risks from a poorly constructed WBS
• Incomplete project definition
• Unclear work assignments, goals / deliverables
• Scope creep
• Budget / schedule overrun (as they were not based on all the work)
• Missing work items

18. How to ….
• Has the project been defined in a charter, mandate, statement of
requirements etc.?
• Is the WBS being developed by the people doing the work?
• What are the projects component parts?
• Have all deliverables / products been identified (internal / external &
interim)?
• What needs to be done?
• Has the project been thought through? Are products decomposed to
processes?
• Has work associated with managing risk been identified?

19. Additional information
• Problem diagnostic checklist from the PMI practice standard for WBS (double
click on gold box)
• Example of a WBS from the PMI practice standard (double click on blue box)

20. Post Script: Work Package Description
• Date
• Person authorised : individual with whom the agreement has been
made
• Work Package Description:
• Product Description: attach the relevant product description(s)
• Techniques / process / procedures to be used
• Interfaces with other products to be satisfied
• Interfaces with other people
• Joint agreement on effort, cost, start & end dates
• Constraints
• Reporting arrangements / Problem handling escalation
OGC 2005 p.391-392