Decomposition
A method for breaking the project scope and deliverables into progressively smaller, easier-to-manage components that can be planned, estimated, and assigned.
Key Points
- Used when creating the WBS and defining activities to structure work.
- Continue breaking down work until items can be reliably estimated, scheduled, and owned (work package level).
- Improves scope clarity, reduces ambiguity, and helps uncover assumptions and risks.
- Typical outputs are the WBS, WBS dictionary, and activity lists with clear responsibilities.
Example
In a data center migration project, the team splits the overall migration into phases (assessment, design, build, migrate, validate). They then decompose the "migrate" phase into server groups and further into tasks such as backup, cutover, verification, and rollback, each with estimates and assigned owners.
PMP Example Question
While developing the WBS, the project team iteratively breaks high-level deliverables into work packages that can be estimated and assigned. What technique are they using?
- Rolling wave planning
- Decomposition
- Delphi technique
- Parametric estimating
Correct Answer: B — Decomposition (breaking scope and deliverables into smaller, manageable parts)
Explanation: Decomposition is used to break deliverables into lower-level components to create the WBS. Rolling wave is about planning detail over time; Delphi gathers expert consensus; parametric is an estimating approach.