問43
頻出度★★☆
システム要件定義において, システム要件を評価する基準として, 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43
ストラテジ系システム企画 › 要件定義
This question's explanation and your answers so far.
解説
問 43
Incorrectア
System integration testing is a downstream process in which the modules built through requirements definition, design, and programming are combined and checked to see whether they work correctly as a system. At the point when requirements definition is being carried out, it has not yet been performed and its results do not exist, so it cannot serve as a criterion for evaluating the requirements. The relationship is in fact the opposite: the system requirements come first, and testing is what later confirms whether they are satisfied.
- イ
正解 The correct answer is イ, consistency with the needs of the system client (the party placing the order). System requirements definition is the most upstream process in the system development life cycle. In it, you draw out what stakeholders such as the client and the user departments want to achieve in their business, organize that into the functions, performance, and constraints the system must have, and finally reach agreement with the client. The requirements produced here become the starting point for all of the later design, programming, and testing, so the only yardstick that can measure whether the requirements themselves are good is not the deliverables of later processes but the needs of the client, which are the source of those requirements. If work moves ahead with requirements that conflict with what the client truly needs, then even if the design, the program, and the tests are all built correctly from a technical standpoint, the finished system cannot be used in the actual business, which is the worst kind of rework. In addition, an error in the requirements becomes more expensive to fix the further downstream it travels, so it is important to compare the content with the client during requirements definition, confirm that nothing is missing and that there is no difference in interpretation, and reach agreement. Therefore the appropriate criterion for evaluating system requirements is consistency with the client needs, and イ is correct.
Incorrectウ
Whether the design method is appropriate is an evaluation viewpoint of the system design process, which decides how the requirements are to be realized. What requirements definition decides is what is to be realized; it is not the stage that specifies the method of realization. Moreover, no matter how excellent the design method may be, it is meaningless if the original requirements conflict with the client needs, so it is not appropriate as a criterion for evaluating the requirements themselves.
Incorrectエ
Comprehensiveness of the test cases is a viewpoint for measuring the quality of test planning and test design; it expresses how thoroughly the conditions that should be tested have been identified without omissions. What it evaluates is the sufficiency of the testing, not the validity of the requirements. In addition, test cases are created on the basis of requirements that have already been fixed, so their comprehensiveness cannot be used as a criterion for judging the requirements at the requirements definition stage.
ここがポイント
- System requirements definition is the most upstream process, the one that decides what is to be realized. Its goal is to draw out the needs of stakeholders such as the client and the user departments, organize them into requirements, and reach agreement with the client (agreement on requirements). The criterion for measuring whether the requirements are valid is consistency with the client needs.
- Distinguish the fact that each process has a different evaluation viewpoint: requirements definition means consistency with the needs, design means the appropriateness of the realization method and the design method, and testing means the comprehensiveness of the test cases and the test results. An error made upstream costs more to fix the further downstream it goes, so confirming the content with the client and reaching agreement at the requirements definition stage is important.
用語