Appropriate budget contingency determination for construction projects: State-of-the-art

Abstract

Contingency is a critical component in the cost estimation process for any construction project. The contingency reserve considers potential costs related to risks and uncertainties associated with construction projects. It is usually assumed to damp any resulting uncertain monetary impact and to prevent project cost overrun. Many contingency calculation methods for construction projects proposed in literature ranged from simple percentage to complex mathematical methods. Deciding the optimum contingency method for a given project at a given phase represents the main challenge in cost estimation process. This study presents a comprehensive compilation of all contingency calculation methods and divided them into three main groups: deterministic, probabilistic, and modern mathematical methods which have been discussed in details. Appropriate method for estimating contingency amount depends on many criteria such as project peculiarity, complexity, ease of method used, and the accuracy level of the estimates. This study proposed a practical guidance approach for construction agencies to choose their appropriate cost contingency method.This research is expected to help agencies/owners in the budget development stage to allocate a contingency budget for their construction projects.