ITPEC IP October 2022 Question 50

I and II — staffing in a waterfall project rises to a peak and falls, while the cost of each correction keeps growing the later it is made.

• •Number of staff members, graph I: requirements definition and basic design need a few people; detailed design, programming and testing need the most; the team shrinks again as the system nears completion and handover.
• •Cost of each correction, graph II: in a waterfall model each phase builds on the approved deliverables of the phases before it. A change or error handled early touches only a document; handled late it means reworking the design, code and tests that already rest on it, so the cost stays low at first and rises steeply toward the end.

Answer (a)

Why not others:

• •(b) I, III — the staffing curve is right, but III has corrections getting cheaper as the project advances, the reverse of how rework piles up
• •(c) II, IV — II as staffing keeps adding people up to the very end, with no fall-off after testing, and IV makes a correction cost the same at every point
• •(d) IV, III — a constant team size through every phase, and corrections that get cheaper over time; both are wrong

Key rule: Settle changes and catch errors as early as possible: in a waterfall project a defect found in a late phase costs many times more to correct than the same defect caught in requirements or design.

Project Management · AI-written, may contain errors