Statistical analysis for comparison of overall performance of projects using Weibull analysis on earned value metrics

Abstract

Most organizations have evaluated project performance primarily through cost and schedule performance measures, such as earned value management, for projects. However, to date, few tools in the project management literature have been proposed for enabling comparisons of the overall performance of projects. This study introduces a simple index, the critical ratio in time (CR(t)), as a measure of the overall performance of a project. The index can be easily calculated on the basis of the earned value (EV) data, which are normally available from a project cost system. Based on the index, a statistical analysis for the comparison of the overall performance of projects using Weibull analysis on EV metrics is proposed. The statistical analysis can be performed on a spreadsheet, such as Microsoft® Excel®. Furthermore, the detailed steps in the analysis are discussed along with an example in which five sample projects are analyzed and compared. Based on the obtained results, the author concludes that the proposed approach on the basis of CR(t) data can provide a robust and effective method for managers to evaluate and compare the overall performance of projects, and can be applicable in evaluating the project whose value has been determined (e.g. contracted projects).

大多數組織評估專案績效主要是以實獲值管理衡量專案成本和時程績效。 然而 ， 至目前專案管理文獻中僅提出少許工具以比較專案間整體績效。 本研究介紹一簡單指標 ， CR(t) (以時間計關鍵比) ， 作為衡量專案的整體績效。 此指標可依從專案成本系統中正常獲得的實獲值資料簡單地計算求得。 根據此指標 ， 本論文提出運用Weibull分析實獲值度量以比較專案整體績效的統計分析 ， 統計分析可在MS EXCEL上執行。 本論文藉由五個案例專案依詳細步驟分析並加以比較專案間之績效。 最後 ， 依照分析比較結果 ， 本論文所提方法可以提供管理者一個穩健且有效地評估和比較專案間之績效的方法 ， 也可以適用於評估專案價值已確定的合約專案。

(*聯絡人: [email protected])

Keywords:

• earned value metrics
• critical ratio in time
• project performance
• Weibull analysis

Keywords:

• 關鍵詞 ： 實獲值度量 ， 以時間計關鍵比 ， 專案績效 ， Weibull分析

Acknowledgements

The author thanks Cheryl Rutledge, Associate Professor of English, Dayeh University, for her editorial assistance, and two anonymous referees for their valuable comments and suggestions.

Notes

(*聯絡人: [email protected])