整合要徑法與作業工率之專案工期預估新模式

A NEW MODEL TO INTEGRATE CRITICAL PATH METHOD AND ACTIVITY UNIT-RATE FOR ESTIMATING PROJECT COMPLETION TIME

10.6652/JoCICHE.202010_32(6).0005

張憲寬(Hsien-Kuan Chang)；余文德(Wen-Der Yu)

完工工期預估 ； 要徑法 ； 作業工率 ； 實獲值 ； 實獲時程 ； 實獲工期 ； Project completion duration estimation ； critical path method (CPM) ； activity unit rate ； earned value ； earned schedule ； earned duration

中國土木水利工程學刊

32卷6期（2020 / 10 / 01）

519 - 530

繁體中文

準時完工是業主最重要的專案績效目標之一，傳統專案完工工期估算方法，包括實獲值、實獲時程及實獲工期等方法，均以總體規劃值與實獲值做為計算之基礎，在不同情境下常忽略要徑轉換對專案工期之影響，而有其根本理論之缺陷。本研究旨在提出一種「基於工率之專案工期預測方法（U-PDEM）」，以作業實際工率結合要徑法（CPM）重新計算專案至完成剩餘之工期（EDTC），以推估專案完工工期（EDAC）。經由實際案例驗證，發現其估計工期之平均絕對百分比誤差（MAPE）精確度，均優於其他傳統專案完工工期估算方法。因此，本U-PDEM方法可做為改善專案工期預測準確性之更佳選擇。

'Completed in time' is one of the most important objectives for project management. Traditional approaches for estimating project completion time based on Earned Value Management (EVM) Earned Schedule Method (ESM) methods, or Earned Duration Management (EDM) method, are erroneous since they are calculated based on the overall planned vs. earned values, which ignore the influence of critical path swapping under different scenarios. This paper proposes a 'Unit-rate based Project Duration Estimating Method (U-PDEM)' that recalculates the project completion duration based on the Estimated Duration to Completion (EDTC) for the activity using the actual unit-rate of the activity during project execution. By comparing the 'Mean Absolute Percentage Error (MAPE)' of the project completion durations estimated by the proposed U-PDEM and those by other traditional methods for a case project, it is found that the proposed U-PDEM outperforms all the traditional methods. It is concluded that the proposed U-PDEM provides a better option to improve the estimation accuracy of project completion time.

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