問37
頻出度★★★
システム開発の見積方法として, 類推法, 積算法, ファンクションポイント法などがある。ファンクションポイント法の説明として, 適切なものはどれか。
平成29年度 春期 ITパスポート試験 問37
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 37
Incorrectア
This describes the so-called itemized (bottom-up) estimation method, which sums up the effort estimated for each work item identified through a WBS to obtain the total effort of the whole system. It uses the effort of work items rather than the number of functions as its basis, which differs from the Function Point method.
- イ
正解 The Function Point method (FP method) is a technique that counts the number and complexity of the 'functions' a system handles — such as input screens, output reports, files used, inquiries, and external interfaces — and estimates the size of the system from their total (the function point value). Choice イ says it 'estimates the size of a system by measuring the number of functions, based on the input screens, output reports, number of files used, and so on', which matches this very definition. A key feature is that it is not easily affected by the programming language or the developer's skill, and it can measure size by the amount of functionality seen from the user's perspective.
Incorrectウ
This describes the program step method (LOC method), which, after estimating the number of program steps (lines of code), obtains the total effort from the standard number of development steps per person-month. Its basis is the amount of code, which differs from the FP method that measures the amount of functionality seen from the user's perspective.
Incorrectエ
This describes the analogy-based estimation method (analogy estimation), which estimates effort by identifying the differences based on a similar system developed in the past. Its basis is comparison with past results, which differs from the FP method that measures the number of functions.
ここがポイント
- The Function Point method is an estimation technique that measures system size by the number and complexity of functions seen from the user's perspective, such as inputs, outputs, files, inquiries, and external interfaces. It is not heavily dependent on the programming language or the developer's skill.
- Distinguishing the main estimation methods: analogy-based (from past similar projects), itemized / bottom-up (summing up WBS work items), program step method (from lines of code), and Function Point method (from the number of functions).
用語