An assessment of current preliminary cost estimating practice in Nigeria
The study assessed the preliminary cost estimating practice in Nigeria with a view to determining the methods in use, the level of accuracy of preliminary cost estimates and the factors influencing their accuracy. A structured questionnaire was used to elicit data from 60 randomly selected qualified Quantity Surveyors in the 156 consulting firms in Lagos State. The data collected were analysed using mean scores, percentages and Factor Analysis. The results indicated that the predominant methods of preparing preliminary cost estimates by consulting Quantity Surveyors were approximate quantities and superficial (floor area) methods. The study also showed that while low rise buildings were under estimated by 8.87%, high rise buildings were over estimated by 23.43%. On overall, building projects were overestimated by 14.36% of their actual costs with project team factors, tendering-related factors, contractor organizational factors, competence-related factors, and project information factors mostly responsible for inaccuracy of preliminary cost estimates.