WBS dictionary
A companion to the WBS that details each WBS element or work package. It captures scope, boundaries, acceptance criteria, ownership, estimates, and other attributes to support planning, execution, and control.
Key Points
- Contains a structured entry for each WBS element, with emphasis on control accounts and work packages.
- Documents description, deliverables, boundaries, acceptance criteria, owner, assumptions, constraints, estimates, resources, risks, and dependencies.
- Forms part of the scope baseline and is controlled through formal change control once baselined.
- Level of detail is sufficient for estimating, scheduling, procurement, and quality planning.
- Links each element to its code of accounts and can reference related requirements, standards, and specifications.
Purpose
Provide clarity on what each WBS element includes and excludes so teams can plan accurately and stakeholders share a common understanding.
- Removes ambiguity that a WBS chart alone cannot resolve.
- Supports consistent estimation and assignment of responsibilities.
- Enables objective acceptance and scope verification.
- Improves change impact analysis by showing dependencies and boundaries.
How to Create
- Start from the approved WBS, scope statement, and requirements baseline.
- Select a template with common fields such as ID, name, description, in/out of scope, deliverables, acceptance criteria, owner, resources, estimates, dependencies, and risks.
- For each WBS element, write a concise description and define clear acceptance criteria and completion definition.
- Record boundaries, assumptions, constraints, and interfaces to other elements or external teams.
- Assign an accountable owner and identify required skills, materials, and quality standards.
- Provide initial duration and cost estimates or references to estimating backups and basis of estimates.
- Cross-reference requirement IDs, specifications, and applicable standards.
- Review with SMEs and stakeholders; iterate until the level of detail enables reliable planning and control.
- Baseline with the scope statement and WBS; activate change control for further updates.
How to Use
- Decompose work packages into schedule activities and sequence them using dependencies identified in the entries.
- Plan resources, costs, and quality controls based on detailed attributes and acceptance criteria.
- Drive procurement statements of work by reusing relevant dictionary fields.
- Validate scope by checking completed deliverables against the acceptance criteria.
- Control scope by comparing proposed changes to documented boundaries and impacts.
- Inform risk identification and mitigation plans tied to specific work packages or interfaces.
- Support communication and handoffs between teams using a single source of truth for each element.
Ownership & Update Cadence
The project manager curates the overall document, while control account managers and work package owners maintain their entries.
- Baseline at the end of planning along with the scope statement and WBS.
- Apply integrated change control to modify baselined entries.
- Use rolling wave planning to elaborate near-term work packages as more information becomes available.
- Version-control updates and communicate changes to all impacted teams.
Example
- WBS ID: 1.2.3.
- Name: Homepage UX Design.
- Description: Create responsive UX design for the website homepage, including wireframes and hi-fidelity mockups.
- Deliverables: Wireframes v1 and v2, style guide updates, final mockups, design handoff package.
- Inclusions: Desktop, tablet, and mobile breakpoints; accessibility at WCAG 2.1 AA level.
- Exclusions: Back-end integration, content authoring, A/B testing implementation.
- Acceptance Criteria: Usability score ≥ 85 in tests, contrast ratios per WCAG, stakeholder sign-off on final mockups.
- Owner: UX Lead; Reviewers: Product Owner, Brand Manager.
- Dependencies: Brand style guide 1.0 approved; user personas finalized.
- Assumptions: Existing component library is available and supported.
- Constraints: Must use corporate design system v3.2; complete within two sprints.
- Resources: 2 UX designers, 1 accessibility consultant, Figma licenses.
- Estimates: Duration 20 working days; Cost 320 hours; Basis: analogous estimate from project X.
- Quality References: WCAG 2.1 AA, Corporate UX checklist v5, Design DoD.
- Risks: Late persona updates could trigger rework; mitigation includes early review gate.
- Completion Definition: All deliverables approved and handed off in the repository with annotations.
PMP Example Question
A stakeholder disputes what is included in a work package during Validate Scope. What should the project manager reference first to resolve the disagreement?
- Project charter.
- Requirements traceability matrix.
- WBS dictionary.
- Issue log.
Correct Answer: C — WBS dictionary.
Explanation: The WBS dictionary specifies boundaries and acceptance criteria for each work package, making it the primary source to confirm what is included. The charter is high level, and the issue log does not define scope details.
HKSM