Cost overrun

Mon 26 March 2018

Recent works by Ahiaga-Dagbui and Smith suggests a rethink of what is traditionally referred to as overruns in construction. They attempt to make a distinction between the often conflated causes of construction cost underestimation and eventual cost overruns. Critical to their argument is the point of reference for measuring cost overruns. Whereas some measure the size of cost overruns as the difference between cost at the time of decision to build and final completion costs, others measure the size of overruns as the difference between cost at contract award and final completion cost.This leads to a wide range in the size of overruns reported in different studies.

Three types of explanation for cost overrun exist: technical, psychological, and political-economic. Technical explanations account for cost overrun in terms of imperfect forecasting techniques, inadequate data, etc. Psychological explanations account for overrun in terms of optimism bias with forecasters. Scope creep, where the requirements or targets rises during the project, is common. Finally, political-economic explanations see overrun as the result of strategic misrepresentation of scope or budgets. Historically, political explanations for cost overrun have been seen to be the most dominant. In the USA, the architectural firm Home Architects has attributed this to a human trait they call "Psychology of Construction Cost Denial", regarding the cost inflation of custom homes.

A less explored possible cause of cost overruns on construction project is the escalation of commitment to a course of action. This theory, grounded in social psychology and organisation behaviour, suggests the tendency of people and organisations to become locked-in and entrapped in a particular course of action and thereby 'throw good money after bad' to make the venture succeed. This defies conventional rationality behind subjective expected utility theory. Ahiaga-Dagbui and Smith explore the effects of escalation of commitment on project delivery in construction using the case of the Scottish Parliament project. Also, a recent study has suggested that principles of chaos theory can be employed to understand how cost overruns emerge in megaprojects. This paper seeks to reclassify megaprojects as chaotic systems that are nonlinear and therefore difficult to predict. Using cases of cost overruns in oil and gas megaprojects, this study makes strong argument that chaos theory can indeed be a silver bullet in finding solutions to the recurring problem of cost overruns in megaprojects.

Category: misc