問31
頻出度★★★
プロジェクトマネジメントのために作成する図のうち, 進捗が進んでいたり遅れていたりする状況を視覚的に確認できる図として, 最も適切なものはどれか。
平成24年度 春期 ITパスポート試験 問31
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 31
Incorrectア
A WBS (Work Breakdown Structure) hierarchically breaks down the deliverables and work of a project and lists them all the way down to the smallest manageable units (work packages). Its purpose is to show the overall picture and structure of the work to be done. Because it has no time axis, it cannot express when each task is scheduled to start and finish, nor how far the work has progressed so far. It is a diagram used at the stage before the schedule is drawn up, so it cannot be used to check whether progress is ahead of or behind schedule.
- イ
正解 The correct answer is イ, the Gantt chart. A Gantt chart lists the tasks along the vertical axis and takes time (dates, weeks, and so on) along the horizontal axis, showing each task from its start to its end as a horizontal bar. If you draw the actual bar next to the planned bar (or show the percentage complete as a filled portion) and add a reference line marking today, you can judge visually: when the actual bar extends past the line to the right, the work is ahead of schedule, and when it does not reach the line, the work is behind. Because the correspondence between time and tasks can be read at a glance, it is the diagram best suited to schedule management and to grasping whether progress is ahead of or behind schedule, which matches the requirement in the question exactly.
Incorrectウ
A cause-and-effect diagram (fishbone diagram, Ishikawa diagram) organizes the factors that could cause a given result (characteristic) by branching them out like the bones of a fish. It is one of the seven QC tools of quality control and is used to analyze the causes of a problem or to organize the results of brainstorming. Since it has neither a time axis nor any information about the amount of progress, you cannot read whether a schedule is ahead or behind from it.
Incorrectエ
A Pareto chart arranges data by category as bars sorted from the largest count or amount to the smallest, with the cumulative percentage overlaid as a line. It is likewise one of the seven QC tools, and based on the Pareto principle that a few important items account for most of the whole, it is used to narrow down the items that should be given priority countermeasures. It shows the categories and the relative size of their counts; it is not a diagram that shows the progress of work over the passage of time.
ここがポイント
- Gantt chart = a horizontal-bar schedule chart with tasks on the vertical axis and time on the horizontal axis. By placing the plan and the actual results side by side and comparing them against a reference date, you can visually check whether progress is ahead of or behind schedule; it is the representative diagram for schedule management.
- Learn the roles of the easily confused diagrams separately. A WBS breaks work down hierarchically and lists it out (no time axis), a cause-and-effect diagram organizes causes, and a Pareto chart narrows down the priority items; the latter two belong to the seven QC tools (quality control tools).
用語