Analysis of factors affecting the accuracy of early cost estimate in construction projects

Abstract

Quality early cost estimate can be measured from its level of accuracy. Early cost estimates prepared at the early stage of project inceptions, therefore early cost estimates have an important function as a starting point and a benchmark for project planning and controling in the future project stages. Early cost estimates are prepared based on limited information and supporting data, it couses in early cost estimates has the lowest level of accuracy than any other types of cost estimates. From the perspective of the important function of an early cost estimate, in contrary the low level of accuracy that is produced is a condition of stark contrast. This condition is often encountered during the preparation of early cost estimates of construction projects that why this topic became the basis of this research. This research aims to make an analysis of the relationship factors that affect the accuracy of the early cost estimate. Research data obtained from surveys of construction projects that have been completed in the period 2006-2011. Survey data were analyzed quantitatively to obtain significant variables and formulate a regression model of factors affecting the accuracy of early cost estimates. Quality of cost estimates associated with the accuracy and completeness of the supporting elements depends on: nature of the project, the level of data and information available, techniques and methods used, ability of estimator, and other factor considered while preparing the estimate. The the factors were developed into 54 variables as the basic elements of the preparation of early cost estimates. From the results of multiple linear regression analysis obtained significant factors (<0.05) which affects the level of accuracy of the early cost estimates, as follows.: Geographical location / Site location, Quality level of the estimator / Estimator Expertise; Availability project information / Documents used in Preparing the estimate; the availability of scope of the project; the availability of project documents (preliminary and Size of Project / Scope of the project.