Factors Affecting Cost Estimates for Earthworks in Civil Engineering Projects in Nigeria

Abstract

A large proportion of the Nigeria government’s expenditure on capital project delivery involve civil engineering works, with greater emphasis on road works to create access for the conduct of economic activities by citizens. Most of the works of this scope awarded to indigenous contractors involve large volumes of cut and fill earthworks. Accurately estimating the cost of earthworks for most indigenous contractors is an arduous task owing to the stochastic nature of the input variables. This paper, therefore seeks to identify key factors affecting the accuracy of earthwork cost estimates the civil engineering project in Nigeria and to determine the effect of factors on the level of accuracy of the estimates. The methodology of study involved structured questionnaire survey of 78 indigenous contractors operating in the nation’s South-East and South-South geopolitical zone. Five (5) major factors affecting the accuracy of earthwork cost estimates (contract requirements and equipment, estimator-related, microeconomic, nature of site and site-level management) were obtained by factor analysis using varimax rotation, However, based on ANOVA test of difference, the study found that the differing levels of accuracy of earthwork cost estimates are caused by contract requirements and equipment, estimator-related, and microeconomic factor. Thus, the consideration of these three factors leads to higher levels of accuracy of earthwork cost estimates in civil works. The study recommend that indigenous contractors’ earthwork cost estimator for civil works should give more attention to contract requirements and equipment estimator-related, and microeconomic factor for improved accuracy of their estimates.