問42
頻出度★★★
システム開発プロジェクトのWBS作成における要素分解に関する説明として, 適切なものはどれか。
平成26年度 春期 ITパスポート試験 問42
マネジメント系プロジェクトマネジメント › プロジェクトマネジメント
This question's explanation and your answers so far.
解説
問 42
- ア
正解 ア is correct. A WBS (Work Breakdown Structure) is a tool for breaking a project's deliverables and work down hierarchically so that the scope is made visible with no omissions. The criterion for how far to decompose is exactly what ア states: as a rule, you decompose until the lowest-level elements (work packages) are of a size at which the cost and the time required can be estimated and at which progress can be controlled. If the pieces are too coarse, neither estimation nor progress tracking is possible; if they are too fine, the management cost is no longer worth it. So the level of detail that satisfies both conditions — estimable and manageable — is the appropriate stopping point.
Incorrectイ
Even when the work is outsourced to an external contractor, defining the scope — what is to be produced and how far — remains the responsibility of the ordering party. If the decomposition is entirely entrusted to the contractor, the range, quantity, and acceptance criteria of the deliverables become vague, which invites gaps in scope, misunderstandings, and extra costs. The correct approach is for the ordering party to decompose the deliverables in a WBS and then clearly state the scope of the order.
Incorrectウ
A WBS must include all the work a project requires, with no omissions (not only the deliverables, but also the work of running the project). Communication management activities such as progress report meetings also consume effort and time, so if they are excluded from the decomposition, that amount of work drops out of the plan and the estimate falls short.
Incorrectエ
If you have experience developing a similar system, you can indeed reuse a past WBS as a template and work more efficiently, but that does not mean the decomposition itself may be skipped. Requirements, team structure, constraints, and scope differ from project to project, so you must always redo the decomposition to fit the current project and check its content.
ここがポイント
- As a rule, WBS decomposition is carried out until the lowest-level work packages reach a level of detail at which cost and required time can be estimated and progress can be controlled.
- The WBS is the core of project scope management: it must include, without omission, not only the deliverables but also necessary work such as meetings and management tasks (and for outsourced portions, the ordering party still defines the scope).
用語