建設(shè)工程造價外文翻譯文獻編輯

1、文獻信息：文獻標題： factorsinfluencingaccuracyof constructionprojectcost estimates in pakistan: perception and reality（影響巴基斯坦建設(shè)工程造價估算精確性的感知因素和實際因素）國外作者： farrukh arif， sarosh h. lodi，nida azhar文獻出處： international journal of construction management, 2021,151:59-70字數(shù)統(tǒng)計： 英文 3023 單詞， 17564 字符；中文 5181 漢字外文文獻：facto

2、rs influencing accuracy of construction project cost estimates in pakistan: perception and realityabstractconstruction projects are unique as they are priced before beingconstructed. therefore, accuracy of construction project cost estimates is pivotal in project success. several studies have determ

3、ined factors influencing the accuracy of cost estimates. comparatively less information is available for construction industries in developing countries. this study identified factors influencing the accuracy of cost estimates for construction projects in pakistan. cost data was collected for 46 com

4、pleted construction projects. fourdimensions 60 factors wereconsidered. dimensions included: project characteristics, project team, estimating procedures, and costing related information items. a rigorous analysis framework based on principal component analysis and regression analysis was used. invo

5、lvement of the contractor in the estimation procedure and labour rates were found to be the most significant factors. early involvement of the contractor can result in realistic estimates through timely input from subcontractors, materials suppliers and manufacturers among others. this also helps in

6、 controlling labour costs as most of the construction projects in pakistan employ labour through subcontractors.keywords: cost estimates; pakistan; factors influencing accuracy; estimate bias; estimate consistency; principal component analysis; regression analysisintroductionthe construction industr

7、y is unique in its working as compared to other manufacturing and product development industries. since it is a projec-bt ased activity, every construction project has its own nature, requirements, and characteristics. the uniqueness of construction projects is that they are priced before being cons

8、tructed. therefore, accuracy of project estimates have a pivotal role. this is the reason that more often than not, comparison of actual cost to early cost estimates becomesthe measure of the project team, performance and overall success of the project oberlender & trost 2001. pricing and the profit

9、 required from the constructionproject are decided at the time of bidding and the bid s acceptance halpin & senior 2021. therefore, construction project managers are primarily involved in cost control.this makes it necessary for construction managers to understand different factors that influence th

10、e accuracy of project cost estimates. several researchers have conducted detailed studies in order to determine factors influencingthe accuracy of cost estimates. however, comparatively less informationon this is available for the construction industries in developing countries. realizing this need,

11、 the paper presents a rigorous analysis to determine factors influencing the accuracy of construction cost estimates. the data was collected from 46 construction projects in pakistan. the authors adopted a two-stage statistical analysis framework to determine the perceived and real factors influenci

12、ng the accuracy of estimates of construction project costs.certain conclusions have been drawn and strategic-levelrecommendations are provided, based on results of the analysis, to improve the cost estimation process and to reduce inaccuracy in the construction industry of pakistan.the study present

13、ed in this paper first provides a brief synopsis of similar prior studies conducted from different perspectives. then it provides an account of the research objectives and scope, followed by details on research methodology and data collection. the main part of the paper provides details of the data

14、analysis and itsresults. thisisfollowedbydiscussion ofresults oftheanalysis.finally, strategic-level recommendations are provided for the improvement of cost estimation practices in the construction industry of pakistan which could be equally applicable for other developing construction industries.p

15、rior studiesseveral studies have been conducted related to accuracy of cost estimates for construction projects. on many occa sions, researchers have attempted to measure the impact of certain project characteristics on the accuracy of estimates skitmore 1988;akintoye & fitzgerald 2000. akintoye 200

16、0 conducted a study to identify andunder stand the factors that influence contractors cost estimation practices in the uk it was concluded that the main fac tors influencing cost estimating practices includedthe complexity of the project, the scale and scope of the construction, market conditions, t

17、he method of construction, site constraints and location. aibinu and pasco 2021 conducted a study to explore the accuracy of pr-etender building cost estimates in australia. they identified eight project characteristics and conducted analysis using multiple regression analysis; they found that the a

18、ccuracy of estimates is influenced by project size.on the other hand, certain other studies had not only accounted for project characteristics but also other aspects, such as project team- related factors, estimating procedures, and costing related information items. carr 1989 conducted a study to d

19、efine the basic requirements for developing reliable estimates. he concluded that theaccuracy of the estimate depends on the estimator s ability to see the project from amacro perspective, his experience and judgement skills. ashwarth 1994 concluded that availability of informationon the design, typ

20、e and quality of costdata, type of project, project size, number of bidders on competitive projects, stability of market conditions,personal factors,proficiencyinestimating, and sheer quantitative experience influence the accuracy of estimating the costs of construction work. oberlender and trost 20

21、01 developed an estimate scoring system and consequently software to measure the accuracy of estimates. they found that the accuracy of anearly estimate has four determinants: 1 who was involved in preparing the estimate;2 how the estimate was prepared; 3 what was known about the project; and 4other

22、 factors considered while preparing the estimate. trost and oberlender 2003 conducted factor analysis and multivariate regression analysis to determine a suitablemodel for predicting the accuracy of estimates. they identified five factors that were significant in predicting accuracy. these factors i

23、ncluded: basic process design, team experience and cost information,timeallowedtoprepare the estimate, site requirements, and bidding and labour climate. enshassi et al. 2021 identified factors such as supply of raw materials and equipment, and fluctuations in the cost of building materials as influ

24、encing cost overruns.the study presented in this paper considered all four dimensions of the factorsinfluencing the accuracy of cost estimates: i.e. factors related to project characteristics, the project team, estimating procedures, and information on the project.research objectives and scopethe pr

25、ime objective of this research was to identify the factors that influence the accuracy of construction project cost estimates in pakistan. for this purpose it was deemed necessary to approach the study from two major perspectives: 1 the factors that are perceived to be influencing the accuracy and 2

26、 the factors that did in reality influence the accuracy of cost estimates when analysed using the actual cost bias in the project data.research methodology and data collectiona thorough literature review was performed to identify the key elements that may provide a good means of judging the accuracy

27、 of cost estimates. the literature review was donethroughbooks,conference proceedings, theinternet,andleading construction management and engineering journals. following the identification of the key elements of the survey, some unstructured expert interviews were conducted to verify the key element

28、s as well as identify any further elements relevant to the practices and issues for estimating costs in the local construction industry.a structured questionnaire consisting of two parts was designed parts a and b. part arequested the respondent pesrsonal informatione.g. workexperience, experience a

29、s cost estimator, etc. and company information e.g. type of organization, types of construction work performed, years in business, annual volume of work, number ofpermanent employees, citiesofoperation, etc. part brequested information on project costs e.g. project name, type, client, estimated proj

30、ect cost, total project cost, estimated profit margin, etc.furthermore, a list of 60 factors categorized under four dimensions was provided to the respondents. the respondents were asked to rate the influence of each factor on the accuracy of the cost estimate of the project for which cost informati

31、on was provided on a likertscale of 1 least influentialto 5 most influential.these dimensions included project team pt having 16 factors, project characteristics pc having 19 factors, estimating procedures ep having 14 factors and costing related information items info having 11 factors. the dimensi

32、ons and factors are listed in table 1.project team related factorsproject characteristics related factorspt1 owner s client s experience of the construction typepc1 initial scale and scope of projectpt2 financial status of clientpc2 priority of projectpt3 impact of type of clientpc3 location of the

33、projectpt4 level of involvement of client in the estimation procedurepc4 complexity of designpt5 willingness to investment in projectpc5 complexity of constructionpt6 no of other projects of clientpc6 type of projectpt7 level of involvement of designer in the estimation procedurepc7 market condition

34、 when project was initiatedpt8 level of expertise of designer with construction typepc8 project durationpt9 involvement of contractor in the estimation procedurepc9 project sectorpt10 level of team integrationpc10 technology requiredpt11 attitude of client towards changespc11 project schedulept12 at

35、titude of contractor towards changespc12 project strategypt13 attitude of designer towards changespc13 project locationpt14 level of expertise of contractor with the construction typepc14 site access availablept15 client s priority level of the projectpc15 no. of floorspt16 impact of contract typepc

36、16 gross floor area estimating procedure related factors pc17 scope for changepc18 project needpc19 contract typetable 1. factors influencing accuracyestimating procedure related factorsinformation item and considerations related factorsep1 availability of cost informationinfo1 labour productivityep

37、2 applicability of cost informationinfo2 workforce typeep3 accuracy and reliability of cost informationinfo3 tax calculation method and considerationep4 standard procedure for updating the cost informationinfo4 insurance calculation method and considerationsep5 time allowed for preparing the estimat

38、esinfo5 completeness of project drawingep6 alignment of estimate methodology with available project informationinfo6 completeness of tender documentep7 formality level adopted during the estimation procedureinfo7 labour ratesep8 utilization of checklist to ensure the completeness of the estimateinfo

39、8 material pricesep9 documentation of information used in preparing the estimatinfo9 inflation rateep10 use of computerized toolsinfo10 equipment rateep11 risk assessment method usedinfo11 equipment productivityep12 profit calculation method/procedureep13 project overhead calculation method/procedur

40、e ep14 method used to determine the contingencyinthe next stage, 2 3 pilotsurveys were conducted through face-to-face interviews. however, the purpose of this exercise was not to collect data, but rather to refinethequestionnaire.thus,forthisreason, industryprofessionalsand academicians having exper

41、ience of such surveys as well as knowledge of pakistan construction industry were consulted.thequestionnaire wascirculatedamonggeneralcontractors,speciality contractors, construction management contractors, and design build contractors. the sampling frame for this survey was construction contracting

42、 companies that possess a licence or are a member of the pakistan engineering council pec, which is a regulatory body for the engineering profession in pakistan. the respondents were asked to provide data on their most recently completed project. the surveys were intended to be filled by the cost es

43、timating personnel related to the project surveyed.a few unstructured interviews with selected respondents from the various groups of contractors were also conducted to clarifytheir responses, to discuss the survey results, and to validate the survey.the details on the survey responses are shown in

44、table 2. a total of 48% valid responses were received, which is rather good for a construction industry questionnaire survey. in a similar study, the researchers used cos-rtelated data for 56 projects and received a response rate of 41% for the accompanying questionnairesurvey aibinu & pasco 2021. t

45、herefore, reliable conclusions can be obtained from the collected data.table 2. breakdown of responsestotal surveys no responsetotal number of potential responsestotal valid responses receivedpercentage of valid responses9535604648%data analysis and resultsgeneral characteristics of respondentsthe m

46、ajority of the responses were collected from karachi. since it is the biggestcity in pakistan, it was considered a representative sample for pakistan s const industry. allof the respondents were local pakistani contractors. most oftherespondent firms which provided data for the projects were general

47、 contractors 77%. the majority of the respondent firms had an annual volume of construction work of between 100 and 500 millionpakistani rupee pkr41%, whilean equal percentage of respondent firms 26% each had an annual volume of construction work of 500 1000 million pkr or 1000 5000 million pkr. the

48、 rest had an annual volume of construction work greater than 5000 millionpkr currently, us$1 102 pkr approximately. a majority of the respondents were either civil engineering managers or project managers. the respondents had an average working experience of around 15 years related to cost estimatio

49、n/cost engineering.the reported projects were mainly in the residential, commercial, and industrial construction sectors 84% as shown in the pie-chart in figure 1. almost an equal number of reported projects were in the public 47% and private 51% sectors.figure 1. type of projects reportedstatistica

50、l analysis frameworkthe analysis procedure was designed to elicit the perceived and real factors influencing the accuracy of the project data that was gathered. the framework for the analysis is shown in figure 2. it has three steps.figure 2. framework of analysisstep 1 focused on finding out the co

51、st bias using the data provided by therespondent contractors on the real costs of the projects. furthermore, normality of cost bias was assessedin order to determine the suitabilityof the data for regression analysis.step 2 included exploratory factor analysis using principal component analysis pca.

52、 the exploratory factor analysis was intended to identify the factors based on exploring the interrelationships among the respective sets of variables the four dimensions. hence, the analysis produced a list of eight significant factors that are perceived to be the factors influencing accuracy. afte

53、rwards, the regression analysis focused on identifying the real factors through exploring the ability of influencing factors to predict variance in bias of the estimates.step 3 used any items out of the 60 influencing factors which were identified as statistically significantlycorrelated with the ta

54、rget cost variable. this regression analysis resulted in a list of real significant factors out of all 60 influencing factors that had affected the accuracy of cost estimates in the projects for which cost data was collected.conclusions and discussion on outcomes of the analysisthe factors that were

55、 identified through pca and were perceived as influencing accuracy included: client levsel of experience of the construction type, level of expertise of contractor, priority of project, initial scale of project, applicability of costinformation, accuracy and reliabilityof cost information, completen

56、ess of tender documents, and labour productivity. none of these eight factors were found to be influential when regression analysis was performed with actual project cost bias data. however, the reason behind the identification of these perceived factors could be the general experience of the respon

57、dents with other projects. one of the reasons that the aforementionedfactorsinfluencetheaccuracyofestimates couldbethe non-availability of commercial cost databases, and accurate labour productivity data.furthermore, regression analysis of all 60 factors with the actual project cost bias data was conducted. the factors of real influence on the accuracy of cost estimates for the projects included in this study were identified. these included: involvement ofcontractor in the estimation procedure, labour rates, number of other projects of client, and attitude of client towards change