Measuring the Impact of Rework on Construction Cost Performance测量返工对工程造价的性能的影响 系别：建筑工程管理系 专业：工程造价 班级： 姓名： 学号： Measuring the Impact of Rework on Construction Cost Performance Bon-Gang Hwang1, Stephen R. Thomas, M.ASCE2, Carl T. Haas, M.ASCE3, and Carlos H. Caldas, M.ASCE4 1 Assistant Professor, Dept. of Building, National Univ. of Singapore, Singapore 117566. E-mail: bdghbgnus.edu.sg 2 Associate Director, Construction Industry Institute, Austin, TX 78759-5316. E-mail: sthomasmail.utexas.edu 3 Professor, Dept. of Civil Engineering, Univ. of Waterloo, Waterloo ON, Canada N2L 3G1. E-mail: chaascivmail.uwaterloo.ca 4 Assistant Professor, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, Austin, TX 78712-0276. E-mail: caldasmail.utexas.edu (Accepted 23 September 2008) Introduction topConstruction projects often experience cost and schedule overruns and rework is a significant factor that directly contributes to these overruns. Research by the Construction Industry Institute (CII) reveals that direct costs caused by rework average 5% of total construction costs (CII 200511). Considering that the U.S. construction industry expended $1,502 billion in 2004 for total installed costs (Bureau of Economic Analysis 20065), almost $75 billion was wasted on direct costs caused by rework in that year alone. Therefore, rework must be considered a significant factor affecting cost performance in the construction industry.Several research efforts (OConner and Tucker 198623; CII 19897; Davis et al. 198912; Burati et al. 19924; Love et al. 1999a20, b21; Love 2002b16; Fayek et al. 200313; Love and Edwards 200417) have attempted to identify and classify the root causes of rework, and to quantify its overall extent. Employing the metric, total field rework factor, and the classification of rework sources developed by CII, this paper assesses the direct impacts of rework on construction cost performance using data from 359 actual projects. More specifically, the objectives of the research described in this paper were: (1) to identify the impacts of rework on construction cost performance for various characteristics of projects; (2) to determine the impacts of different sources of rework on construction cost performance; and (3) to isolate the root causes of rework and recommend possible solutions for those causes.By comparing the impacts of rework according to project characteristics and by measuring sources of rework, those projects most affected by rework are identified. Additionally, those sources of rework having the biggest impact on construction cost performance are discussed. After the analysis of the cost impact of rework is summarized, the root causes of rework will be assessed and possible solutions can be suggested.The recognition of the various impacts of rework is important for project managers. For those projects on which cost tends to be more affected by rework, project managers should focus on minimizing rework by developing systems for addressing the sources of rework. Preproject and quality management plans should be drafted with an understanding of the causes of rework in order to minimize its impact. This paper provides an understanding of the impact of rework on construction cost performance, thus helping to reduce rework and improve project cost performance.Background topAccording to Love (2002b)16 rework has various definitions and interpretations within the construction management literature: terms for it include “quality deviations” (Burati et al. 19924), “nonconformance” (Abdul-Rahman 19951), “defects” (Josephson and Hammarlund 199914), and “quality failures” (Barber et al. 20003). Love et al. (2000)22 characterize rework as the unnecessary effort of redoing a process or activity that was incorrectly implemented the first time. Similarly, field rework is defined as activities that have to be done more than once or activities that remove work previously installed as part of a project (CII 20018). Based upon CIIs definition, Fayek et al. (2003)13 proposed a definition of rework that adds the constraint that rework caused by scope changes and change orders from owners should not be classified as rework. In the sense of conformance, there are two main definitions of rework (Love 2002b16; Fayek et al. 200313). The first definition is that rework is the process by which an item is made to conform to the original requirements by completion or correction (Ashford 19922). The second definition given by the Construction Industry Development Agency (1995)6 holds that rework involves doing something at least one extra time due to nonconformance to requirements. Although the wording of the definitions and interpretations of rework vary, there is a common themerework means having to redo work due to nonconformance with requirements.Several studies hav