Cost Estimation of Industrial Risk in the Bidding Process

Project cost estimation in the bidding process is a critical concern for the competitiveness and profitability of an engineering and contracting company. Estimates which diverge as little as possible from actual costs have to be made on the basis of relatively limited information. Of the macro-items contributing to the overall cost of a plant project, those linked to engineering activities have been growing continuously in percentage terms for a number of years and have thus become the object of considerable interest. Moreover, since these items are difficult to standardise, estimation is particularly difficult. A method able to produce reliable estimates for these activities could certainly be usefully transferred to other project stages. The methodology proposed to formulate a bid estimate for a HAZOP study envisages the joint use of three tools to produce more accurate estimates and improve the quality of decisions through explicit assessment of the risk of over-estimating (or under-estimating) the cost. First, an analytical estimation model based on improved structuring of available information provides more accurate estimates and facilitates the use of IT applications. Second, company knowledge gained in previous projects is structured and maintained in order to ensure continuous improvement in estimation. This information can be used to improve over time the understanding of the determinant values in the model itself, so obtaining increasingly accurate estimates and probability distributions which take account of historical errors. Finally, a simulation technique provides the probability distribution of the overall cost and thus the confidence interval of the estimates.