問4
頻出度★★★
ソフトウェアの設計品質には設計者のスキルや設計方法, 設計ツールなどが関係する。品質に影響を与える事項の関係を整理する場合に用いる, 魚の骨の形に似た図形の名称として, 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4
ストラテジ系企業活動 › 業務分析・データ利活用
This question's explanation and your answers so far.
解説
問 4
Incorrectア
An arrow diagram represents activities with arrows and the junctions between activities with circles (nodes), and is used to work out a schedule and the critical path from the order of activities and the days they require (a PERT chart). It is a tool for scheduling and progress management, not a diagram that organizes quality factors in the shape of a fish skeleton.
- イ
正解 The correct answer is “イ Cause-and-effect diagram”. In a cause-and-effect diagram, the “characteristic” you want to improve (here, the design quality of the software) is placed at the right end, and from the backbone pointing toward it, large bones and small bones branch out so that the “factors” (the designer's skills, design methods, design tools, and so on) can be written in hierarchically. Because it looks like a fish skeleton, it is also called a fishbone chart. The two clues in the question, “organize the relationships among factors that affect quality” and “a diagram shaped like a fish skeleton”, are exactly a description of the purpose and the shape of the cause-and-effect diagram, so this is the appropriate choice. It is one of the seven QC tools, and is used to bring out the causal relationship between a result (characteristic) and its causes (factors), for tracking down causes and considering improvement measures.
Incorrectウ
A Pareto chart arranges items such as defects or complaints as bars in descending order of count, and overlays their cumulative percentage as a line. It is used to find “which items account for most of the whole” (a focus on the vital few); its shape is bars plus a line, not a fish skeleton, and it does not show relationships among factors.
Incorrectエ
A matrix diagram places two sets of elements along rows and columns and records at each intersection whether a correspondence exists and how strong it is, forming a grid. It is indeed used to organize relationships, but its shape is a table (a grid), not a fish skeleton, and it has no structure for drilling down from a characteristic into large bones and small bones of factors.
ここがポイント
- Cause-and-effect diagram (fishbone chart) = a diagram that organizes the causal relationship between a characteristic (result) and its factors (causes) in the shape of a fish skeleton. It is one of the seven QC tools, used to track down causes and consider improvement measures.
- Learn the QC-family diagrams as a set, remembering both shape and purpose: Pareto chart = narrowing down the key items (bars plus a cumulative line); arrow diagram = scheduling and the critical path; matrix diagram = expressing the correspondence between two sets of elements in a grid.
用語