N 社は，携帯情報端末用アプリケーションソフトウェア（以下，携帯アプリという）の商品開発プロジェクトを，4 月 1 日に社外秘で立ち上げた。携帯アプリの商品開発プロジェクトは，マーケティングを自社で，ソフトウェア開発を外部調達で行う。 〔7 月 1 日までのプロジェクトの経緯〕 (1) N 社の体制：4 月のプロジェクト立上げ時の構成員は，プロジェクトマネージャ 1 名とプロジェクトメンバ 3 名であったが，6 月からは A さんが参加し総勢 5 名になった。 (2) ソフトウェア開発：B 社及び C 社と守秘義務契約を締結後，この 2 社に見積書を提出してもらい，6 月中旬に B 社と請負契約を締結した。 (3) プロジェクト期間短縮：プロジェクト期間は当初 7 か月の計画で開始したが，競合他社が類似商品を開発する動きがあることから，6 月下旬に全体で 1 か月プロジェクト期間を短縮することを検討し実施した。前提条件は，次の 2 項目とした。 ・商品仕様と請負業務範囲は変更しない。 ・商品発表は，当初ソフトウェア開発の完了時に行うこととしていたが，ソフトウェア開発完了の 0.5 か月前に前倒しする。 〔契約変更と工程管理〕 プロジェクト期間短縮を B 社と協議したところ，次の回答があった。 “ソフトウェア開発工程の作業に要員を追加すれば，作業の完成を早めることが可能である。要員追加に伴い一時生産性が低下し，開発工数が増加するので，そのコスト増分が認められれば対応する。バグ増加などのリスクは少ない。” N 社と B 社は，この内容で合意し，請負契約の変更契約を 6 月末に締結した。 図 1 はプロジェクト期間を 1 か月短縮した変更計画を含むガントチャートである。N 社は，7 月 1 日からこのガントチャートの変更計画に従って工程管理を開始した。 N 社は, 7月1日から図1のガントチャートの変更計画に従って工程管理を開始した。 この変更計画で, プロジェクト期間を全体で1か月短縮することを可能にする対策の説明として, 適切なものはどれか。
平成25年度 秋期 ITパスポート試験 問88
This question's explanation and your answers so far.
問 88
※ Our check while writing this explanation could not fully confirm the published answer; scoring follows IPA's official key.
Incorrectア
If you shorten the development by 0.5 months and move up the acceptance testing and acceptance inspection by 0.5 months, the acceptance testing and acceptance inspection finishes at the end of September. However, since nothing is done about the distribution planning and promotion work, it stays as in the original plan, from mid-September to the end of October, and the project's finish date remains the end of October, unchanged. In other words, with this measure alone the shortening is zero months. What determines the overall duration is the activity that finishes last, so unless you move that, no effect appears.
- イ
正解 Figure 1 is a Gantt chart whose horizontal axis is a monthly scale from April to October, with three rows — original plan / modified plan / actual results — lined up for each activity. Reading the original plan first: external procurement management (Company B's software development work) runs from mid-June to mid-September, the acceptance testing and acceptance inspection from mid-September to mid-October, and the distribution planning and promotion work from mid-September to the end of October; the one that finishes last is the distribution planning and promotion work, so the end of the project as a whole is the end of October. Reading the modified plan next: external procurement management runs from mid-June to early September (= shortened by 0.5 months), the acceptance testing and acceptance inspection from early September to the end of September (= moved up by 0.5 months, its duration still one month), and the distribution planning and promotion work from mid-August to the end of September (= moved up by one month, its duration still 1.5 months), so the end of the whole becomes the end of September = exactly one month of shortening. What matters here is that, for the shortening to take effect, the "activity that finishes last" must be moved up. If you only shorten the development by 0.5 months and move up the acceptance testing and acceptance inspection by 0.5 months, the distribution planning and promotion work, which finishes last, stays at the end of October, so the whole does not shrink. Conversely, if you move up only the distribution planning and promotion work, the acceptance testing and acceptance inspection remains until mid-October. Only when both are put in place does everything fit within the end of September. Furthermore, the start of the moved-up distribution planning and promotion work (mid-August) overlaps by 0.5 months with Company B's software development work, which is still under way (finishing in early September). In other words, the modified plan in Figure 1 is a combination of three measures — "shorten the development by 0.5 months + move up the acceptance testing and acceptance inspection by 0.5 months + move up the distribution planning and promotion work so that it runs in parallel with the development for 0.5 months" — and イ, which states exactly this, is the correct answer.
Incorrectウ
In the modified plan of Figure 1, what external procurement management (Company B's software development work) is shortened by is the 0.5 months from mid-June–mid-September to mid-June–early September, not one month. As a reading of the figure, this is wrong. In addition, even if the development were shortened by one month, unless the subsequent acceptance testing and acceptance inspection and the distribution planning and promotion work are moved up, the distribution planning and promotion work, which finishes last, stays at the end of October, so the whole is not shortened by a full month.
Incorrectエ
Moving up the start of the distribution planning and promotion work by one month, from mid-September to mid-August, does match the modified plan in Figure 1, but the length of the parallel work is different. In the modified plan, Company B's software development work itself is also shortened by 0.5 months and finishes in early September, so the overlap is the 0.5 months from mid-August to early September, not one month. Also, with this measure alone the acceptance testing and acceptance inspection finishes in mid-October as in the original plan, so the overall shortening stops at 0.5 months and does not reach the target of one month.
- A Gantt chart is a progress management chart with time on the horizontal axis and activities on the vertical axis; by drawing the original plan, the modified plan, and the actual results side by side, you can compare them against the scale and read off which activity was moved up or shortened, and by how much.
- What determines a project's overall finish date is the activity that ends last. Even if some activity is shortened, the overall duration does not shrink unless the activities remaining behind it, and the activities that run in parallel and continue to the very end, are also moved up. Conversely, parallel work in which part of an activity is started so that it overlaps, without waiting for the preceding activity to be completed (fast tracking), is an effective means of shortening the overall schedule.