CONCEPT OF ESTIMATING

THE CONCEPT OF ESTIMATING

Estimating involves the assessment of probabilities and risks making complete accuracy impossible. However within the limits of achievable accuracy, it can be stated that the greater the accuracy, the higher the cost of achieving that accuracy. There is usually a point beyond which the cost is increasing and estimate’s accuracy is greater than the benefit to be gained (Duncan 1996).

Cost estimating for building projects traditionally starts with quantification, a time‐intensive process of tallying components from printed drawing sets or contract documents. Estimators utilize methods from spreadsheets to costing applications to produce the project cost estimate. This process is prone to human error and tends to propagate inaccuracies that creep into the tallies. Researcher and experts give cost estimating different definition, thus the following paragraphs state some of them.

Cost estimation can be explained as the determination accounts for materials, labor, equipment and many other variables that affect conducting that activity (Al-Bani, 1994). Estimating is the process of looking into the future and trying to forecast project costs and resource requirements (Ashworth, 1984). An estimate is a judgment, opinion, forecast or prediction. It is a judgment or opinion of the cost of a process, product, project or service. It is a prediction or forecast of what a work output or work activity will cost (Stewart 1991).

Finally, estimating is a collection and analysis of the bill items which influences and contributes to the cost of the project (Clough, 1986). Consequently, all those definition are similar describing cost estimating as being the process of guessing and foreseeing the future costs of a project or product before it actually exist.