ABSTRACT
Calculating the costs of a proposed building or civil engineering project has traditionally consisted of applying appropriate unit rates to measured quantities and descriptions of proposed works. At the design stage of a project the measurements and descriptions may represent little more than the spatial requirements provided by the client. At the contractor’s stage, these may be sufficiently detailed to describe the various components and processes of the project. In either case, quantifying the work can be reasonably precise. However, the judgement involved in allocating correct prices to these quantities and descriptions is extremely variable. Hence two distinct types of model have evolved.
