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Abstract
Tendering is the normal means by which contractors in the construction industry solicit business. Bidding models have been devised to help contractor bid for jobs but these tend to have limited applications because they generally treat uncertainties stochastically (randomly). Contractors have used to react to these uncertainties by rules of thumb and heuristics. However, research findings by cognitive psychologists in early 1970s that subjective judgments are fallacious have aroused much hot debate. The debate has centred around the so-called normative theory of decision making and the methodology of performing the studies. On the one hand, it was argued that uncertainties in the construction industry were the result of its being a humanistic system and therefore subjective judgments made under uncertainty were inevitable. On the other hand, if professional education in the construction industry has some usefulness in training its practitioners to make sensible decisions then there should be less evidence of bias and fallacies as described by the psychologists (Hypothesis 1). Empirical studies done with domain specific subjects with domain specific questions supported this hypothesis.
In recent years, risk management in construction has become popular and been accepted as a means to tackle some of the uncertainties inherent in construction works. The modelling of the perception of risk is one of the most crucial steps in the whole risk management process; and has mostly been done by a 3-point triangular model. Fuzzy sets theory was introduced with an intention of modelling the risk perceptions of construction professionals. Five linguistic expressions were devised to test the consistency of these perceptions. It was hypothesized that there was consensus among construction professionals with respect to the perception of a selected number of linguistic terms to express uncertainty and that fuzzy sets theory modelled these perceptions better than the traditional methods (Hypothesis 2). It was found, empirically, that there was high consensus among the subjects as to the meaning of these terms; and that the use of the traditional 3-point triangular model led to judgmental bias.