問36
頻出度★★★
開発期間 10 か月, 開発の人件費予算 1,000 万円のプロジェクトがある。5 か月経過した時点で, 人件費の実績は 600 万円であり, 成果物は全体の 40% が完成していた。このままの生産性で完成まで開発を続けると, 人件費の予算超過はいくらになるか。
令和3年度 ITパスポート試験 問36
マネジメント系プロジェクトマネジメント › プロジェクトマネジメント
This question's explanation and your answers so far.
解説
問 36
Incorrectア
'1,000,000 yen' is the overrun you would get if the total cost at completion were estimated at 11,000,000 yen. It merely gives the difference between the budget apportioned by elapsed time (10,000,000 yen × 5/10 months = 5,000,000 yen) and the actual 6,000,000 yen — that is, it answers only the 'overrun as of now'. It does not account for the fact that the remaining 60% of the work will also exceed the budget at this same low productivity, so it is a large underestimate. Incorrect.
Incorrectイ
'2,000,000 yen' is the overrun if the total cost were estimated at 12,000,000 yen. This is the classic mistake of extrapolating progress by 'elapsed time' rather than by 'the completion rate of the deliverables' (6,000,000 yen × 10 months ÷ 5 months = 12,000,000 yen). Since what has actually been completed is 40%, not 50%, extrapolating by the time ratio overestimates productivity. Incorrect.
Incorrectウ
'2,500,000 yen' is the overrun if the total cost were estimated at 12,500,000 yen. It falls short of the correct estimate 'actual 6,000,000 yen ÷ completion rate 0.40 = 15,000,000 yen' and underestimates the cost needed for the remaining 60% of the work. Only 6,000,000 ÷ 0.40 correctly reflects the current productivity. Incorrect.
- エ
正解 This question asks you to first estimate the total cost at completion (EAC) and then find its difference from the budget. EAC can be roughly obtained as 'actual cost incurred so far ÷ completion rate of the deliverables'. At this point the actual labor cost is 6,000,000 yen and 40% of the total deliverables are complete, so if development is carried through to 100% at this same productivity, the total cost becomes 6,000,000 yen ÷ 0.40 = 15,000,000 yen. Since the labor-cost budget is 10,000,000 yen, the budget overrun = 15,000,000 − 10,000,000 = 5,000,000 yen. Therefore choice エ is correct.
ここがポイント
- Rough EAC (total cost at completion) = actual cost ÷ completion rate of the deliverables; budget overrun = EAC − budget. In this question, 6,000,000 yen ÷ 0.40 − 10,000,000 yen = 5,000,000 yen.
- Extrapolate progress by 'the completion (earned-value) rate of the deliverables', not by 'elapsed time' (the fundamental idea of EVM / earned value management).
用語