Work Breakdown Structure (WBS)

A Work Breakdown Structure (WBS) organises a project's total scope into a hierarchical structure of deliverables and work packages. It is a fundamental planning tool that ensures nothing is overlooked and that the scope is fully understood.

WBS structure:

• Level 1: The project itself (top level)
• Level 2: Major deliverables or phases
• Level 3: Sub-deliverables or major tasks
• Level 4: Work packages (lowest level of decomposition)

WBS types:

• Deliverable-based: Organised around what is produced (recommended by PMI)
• Phase-based: Organised around project phases
• Functional-based: Organised around business functions or teams

WBS creation rules:

• 100% rule: The WBS must capture 100% of the project scope
• Mutually exclusive: Work packages should not overlap
• Outcome-oriented: Focus on deliverables, not activities
• Progressive elaboration: Detail increases at lower levels
• Work packages: The lowest level should be estimable, assignable, and manageable

Benefits of WBS:

• Ensures no scope is missed (the 100% rule)
• Provides a basis for cost and time estimation
• Enables clear assignment of responsibility
• Supports progress tracking at multiple levels
• Facilitates communication about project scope
• Serves as a foundation for the project schedule

WBS and other project management tools:

• The WBS feeds into the project schedule (adding durations and dependencies)
• The WBS feeds into the cost estimate (estimating each work package)
• The WBS feeds into the RACI matrix (assigning responsibility to work packages)
• The WBS supports risk identification (analysing each work package for risks)

WBS creation approach:

• Start with major deliverables
• Decompose each deliverable into its components
• Continue decomposing until work packages are manageable (typically 8-80 hours of work)
• Validate with the team and stakeholders
• Use the WBS dictionary to define each element clearly