問55
頻出度★★★
1,800万円の予算でプログラムを60本作成するプロジェクトにおいて, 開始後20日経った現在の状況を確認したところ, 60本中40本のプログラムが完成し, 1,500万円のコストが掛かっていた。このままプロジェクトを進めた場合, 予算に対する超過コストは何万円か。ここで, プログラムの規模及び生産性は全て同じであるとする。
平成30年度 春期 ITパスポート試験 問55
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 55
Incorrectア
300 is the mistake of taking the remaining budget (1,800−1,500=300 ten-thousand yen) directly as the answer. What is asked is by how much the budget will be exceeded at completion, not the remaining budget at the current point. If work proceeds at the actual pace, the total cost becomes 2,250 ten-thousand yen and the overrun is 450 ten-thousand yen.
- イ
正解 In cost management, you extrapolate the actual productivity (cost spent ÷ number completed) to the whole workload to estimate the total cost at completion, then find the overrun from its difference against the budget. At the point 20 days after the start, 40 of the 60 programs are finished and 1,500 ten-thousand yen has been spent, so the actual cost per program is 1,500÷40=37.5 ten-thousand yen. Since the size and productivity of all programs are exactly the same, the remaining 20 programs proceed at the same pace. The total cost when all 60 are completed is 37.5×60=2,250 ten-thousand yen. The budget is 1,800 ten-thousand yen, so the overrun cost is 2,250−1,800=450 ten-thousand yen. Therefore “イ” is correct.
Incorrectウ
600 mistakes the remaining-work cost (20×30=600 ten-thousand yen), estimated for the remaining 20 programs at the budgeted unit cost (1,800÷60=30 ten-thousand yen per program), for the overrun. But each program actually cost 37.5 ten-thousand yen, and estimating with that actual unit cost is correct. Calculating with the budgeted unit cost underestimates the overrun.
Incorrectエ
750 is the remaining-work cost (20×37.5=750 ten-thousand yen), estimated for the remaining 20 programs at the actual unit cost (37.5 ten-thousand yen per program). This is the cost still to be incurred going forward, not the amount over budget. Subtracting the budget of 1,800 ten-thousand yen from the total cost of 2,250 ten-thousand yen gives 450 ten-thousand yen, which is the overrun.
ここがポイント
- Extrapolate the actual productivity (actual cost ÷ number completed = actual cost per program) to the whole workload to estimate the total cost at completion, then find the overrun cost from the difference against the budget (the idea of cost / budget-vs-actual management and EVM).
- “Budget overrun cost”= forecast total cost − budget. Do not confuse it with the remaining-work cost or the remaining budget.
用語