CDT505 Chap.3 Scope Definition and Work Breakdown
Scope Definition and Work Breakdown
Turn needs into accepted deliverables
Requirements describe stakeholder needs and conditions, while the scope statement defines authorised boundaries, deliverables, assumptions and exclusions. The work breakdown structure decomposes the result into manageable deliverables and work packages. Its one-hundred-per-cent rule tests completeness and non-duplication at every level.
A controlled work package needs a tangible output, observable acceptance criteria and one accountable owner so that schedule, cost and risk can trace back to the same scope.
Protect traceability into later plans
A noun-based WBS shows what must exist, whereas an activity list shows what people expect to do.
The distinction matters because the schedule, estimate and risk register should all trace to authorised deliverables. Acceptance criteria make completion observable, and exclusions let stakeholders challenge the boundary before delivery. When a requirement changes, traceability reveals the affected package, activities, owner, cost and risk.
Scope control can then assess a coherent change rather than repairing disconnected documents after work has started.
What this chapter covers
- 01
Requirements and scope boundaries
- 02
Deliverables against activity lists
- 03
Hierarchical WBS decomposition
- 04
The one-hundred-per-cent rule
- 05
Work packages and accountable owners
- 06
Acceptance, validation and change control
Worked example · free
Repair an activity-based WBS
- 3Identify duplication and missing deliverable logic.
- 3Reframe branches as outputs.
- 2Add acceptance criteria and ownership.
Key terms
- Requirement
- A documented need or condition that a project result must satisfy.
- Scope Statement
- The approved description of deliverables, boundaries, assumptions, exclusions and acceptance.
- Work Breakdown Structure
- A hierarchical decomposition of the complete authorised project scope.
- Work Package
- A controlled WBS element that can be estimated, scheduled, assigned and accepted.
- Acceptance Criteria
- Observable conditions used to decide whether a deliverable is complete and correct.
Scope Definition and Work Breakdown FAQ
How do I test the impact of a scope change?
Trace the request from requirement to deliverable and work package, then identify affected activities, cost, risk, acceptance evidence and ownership. State who can approve the change and which baseline elements remain untouched. This connected trace prevents one document from being updated while the schedule, budget or risk register silently preserves an obsolete plan.
What does the one-hundred-per-cent rule mean?
The children under each WBS parent must represent all of that parent and nothing outside it. The rule tests completeness and avoids duplicate work. It does not require percentages to be printed inside boxes or make an activity list into a WBS.
How deep must the individual assignment WBS go?
The current brief requires at least three levels and decomposition to the work-package level. One selected package must also describe its tangible deliverable, acceptance criteria and responsible owner, which shows that the hierarchy can support control.
How is scope validation different from quality control?
Quality control provides inspection or test evidence about correctness. Scope validation is the stakeholder decision to accept a completed deliverable against agreed criteria. A deliverable can pass a technical check yet still fail an authorised business acceptance condition.
Assessment move
Choose one small project and write its need, objective, principal requirements, exclusions and acceptance decision on separate lines. Turn the result into a noun-based WBS with at least three levels. At every parent, read the child boxes as a sentence: together they must describe all of the parent and nothing outside it. Circle duplicated work and mark any condition required for delivery that appears nowhere.
This is the practical use of the one-hundred-per-cent rule. Select two work packages and prepare a mini dictionary entry for each. State the tangible output, objective acceptance criteria, accountable owner, estimate basis and interfaces with other packages. Avoid criteria such as professional or high quality; replace them with observable conditions and an accepting role.
Next, derive scheduled activities from the packages and draw a trace line back to the WBS. Add one cost and one risk to the same chain. If an activity, cost or risk cannot trace to authorised scope, decide whether it is missing scope or unnecessary work. Practise validation and control as different decisions: validation accepts a completed deliverable, while control assesses a proposed change to the baseline.
Build two short cases where quality evidence passes but stakeholder acceptance fails, and where the stakeholder accepts a documented minor defect. Before submitting the assignment, compare every network activity with the WBS and every WBS branch with the objective.
Check that planning and closure work are present, that a person or department has not been mistaken for a deliverable, and that one work package satisfies the current brief's output, criteria and owner requirements.
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