19-Soft-A5 Requirements and Specifications · May 2015
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams, May 2015 — 04-Soft-A5, Requirements and Specifications (open book, one book of the candidate's choice, 3 hours, no calculator). The paper has four parts: Part 1 (30%) is ten statement/reason items on requirements-engineering theory; Part 2 (25%) is a two-page essay on the requirements-elicitation process; Part 3 (25%) covers non-functional requirements, including three NFRs for a life-critical avionics system; Part 4 (20%) asks for the seven characteristics of an excellent individual requirement and the three characteristics of an excellent requirements collection. This solution answers every part and every sub-item in full as a study resource.
Reference texts. Sommerville, Software Engineering, 10th ed., Ch. 4 (Requirements Engineering) & Ch. 5 (System Modeling); Pressman, Software Engineering: A Practitioner's Approach, 9th ed., Ch. 8–9; SWEBOK v4, Requirements Engineering KA; ISO/IEC/IEEE 29148 (requirements quality characteristics); ISO/IEC 25010 (SQuaRE quality model, used for the avionics NFRs in Part 3); Karlsson & Ryan and Karlsson, Wohlin & Regnell on requirements-prioritization scales (Part 1, items 1–2); Ruhe, Product Release Planning: Methods, Tools and Applications, on precedence/coupling constraints in release planning (Part 1, item 5); Lauesen, Software Requirements: Styles and Techniques, on requirement levels, task descriptions and focus groups (Part 1, items 4, 8 and 10; Part 2).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
Approach. Each item is evaluated in two independent steps — is the statement itself defensible under the requirements-engineering literature, and is the reason a factually correct claim — before asking whether the reason logically explains the statement; the combination of the three judgements picks the letter. Per the paper's own Note 1, where a term is genuinely ambiguous the assumption made is stated inline.
| Item | Answer | One-line basis |
|---|---|---|
| 1 | D | Waiting entirely till the end is wrong; "requirements get clearer over time" is a true but non-rescuing fact. |
| 2 | D | Backwards — ratio-scale (pairwise) methods cost more work, not less; the fraction-eliciting reason is true. |
| 3 | E | Effort should be risk-proportioned, not uniform; "same accuracy = best use of effort" is also false. |
| 4 | E | Prototype success does not verify the implementation; an integrator limiting its responsibility raises, not lowers, the customer's risk. |
| 5 | C | More constraints shrink the feasible-plan set (true); the reason claims the opposite (false). |
| 6 | A | Losing the written record is a real risk, and insufficient communication intensity is exactly why. |
| 7 | C | TDD does raise traceability, but via tests LINKING to design/code — the reason denies that link. |
| 8 | D | Task descriptions are the domain-level technique (screens/prototypes are design-level); they do omit the "how", by design. |
| 9 | A | Cross-cutting scope + sliding-scale targets are the textbook reasons quality reqs are harder to pin down. |
| 10 | A | Focus groups end with each stakeholder's top-wish list, which is how every stakeholder is made to get something. |