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What Is The 100% Rule In WBS Development? - The Project Manager Toolkit
The Project Manager Toolkit
Overview
The 100% rule in Work Breakdown Structure (WBS) development ensures that a project's scope is fully captured. It dictates that a WBS must include all work required for project completion, with no omissions or extraneous elements. This principle applies hierarchically, meaning the sum of sub-tasks must equal the parent task at every level. Adhering to the 100% rule prevents scope creep, avoids work duplication, and facilitates accurate cost estimation and progress tracking, forming the basis for a well-defined project plan.
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Chapters
- The 100% rule states that a WBS must encompass all work required for the project.
- It means including every necessary task, deliverable, and subtask without adding anything outside the project scope.
- This rule applies at every level of the WBS hierarchy.
This rule ensures that the project plan is comprehensive, leaving no room for misunderstandings about what work is included or excluded.
If a parent task is 'build a website,' the sum of its sub-tasks (designing the homepage, coding the contact form, testing pages) must equal the total effort for building the entire website.
- At any level of the WBS, the total work of the child elements must equal the work of the parent element.
- Each work package's activities must fully account for the work needed to complete that package.
- This hierarchical completeness prevents work from being left out or duplicated across different branches of the WBS.
Understanding this hierarchical application ensures that the decomposition of work is logical and that no work falls through the cracks or is counted twice.
If a work package is 'develop user interface,' its constituent activities like 'design mockups,' 'create style guide,' and 'implement front-end code' must collectively represent the entirety of the UI development effort.
- It provides a complete project overview, aiding in scheduling and resource allocation.
- It acts as a defense against scope creep by clearly defining project boundaries.
- It prevents overlapping tasks, ensuring efficiency and clarity in responsibilities.
- It simplifies cost estimation and progress tracking due to clear task definitions.
These benefits directly contribute to better project control, reducing risks and increasing the likelihood of successful project delivery.
By having a complete WBS, a project manager can confidently estimate the total budget and timeline, knowing that all necessary work has been factored in.
- During WBS creation, focus on 'what' needs to be done, not 'how' it will be done.
- The WBS should represent the final deliverables and project outcomes.
- Break down tasks until they are manageable for assignment and estimation.
- The 100% rule is fundamental for creating a structured and manageable project plan.
This approach ensures the WBS remains focused on the project's objectives and deliverables, providing a clear roadmap for execution.
For a 'new product development' project, the WBS should include high-level tasks like 'design prototype,' 'source materials,' and 'test product,' which are then further broken down.
Key takeaways
- A Work Breakdown Structure (WBS) must account for 100% of the project's work.
- The 100% rule applies recursively, ensuring completeness at every level of task decomposition.
- Strict adherence to the 100% rule is crucial for preventing scope creep and work duplication.
- A well-defined WBS based on the 100% rule simplifies project planning, estimation, and control.
- Focus on deliverables and outcomes, rather than the 'how-to,' when initially building the WBS.
- The 100% rule is the bedrock of a robust and reliable project plan.
Key terms
Work Breakdown Structure (WBS)100% RuleScope CreepDeliverablesWork PackageTask DecompositionProject ScopeProject Planning
Test your understanding
- What is the core principle of the 100% rule in WBS development?
- How does the 100% rule apply hierarchically within a WBS?
- Why is it important to focus on deliverables rather than the 'how' when creating a WBS?
- What are the primary benefits of strictly following the 100% rule for project managers?
- How can the 100% rule help prevent scope creep?