Developing a Rating Score for Out-of-Sequence Construction

Abstract

Out-of-sequence (OOS) construction takes place when an activity or series of activities is not performed according to baseline planned logical productive sequencing. A previous expert-based study by the authors—which has already been published—was the first to provide an industry-wide assessment of OOS work that identified 88 causes of OOS work and quantified them in terms of likelihood of occurrence, relative impact, and risk rating. This paper moves forward to create OOS risk tiers and OOS rating score to measure a project’s susceptibility to the risks of OOS in comparison with the industry averages. Series of statistical tests were used to determine the number of risk tiers, allocate the OOS causes to these risk tiers, and define cutoff scores for the different risk tiers. Ultimately, the developed OOS decision support tool was evaluated through expert reviews and direct application on 11 different construction projects. For best results, the associated stakeholders should use the proposed tool at the planning stage of their projects to identify the relevant risks and take the proper actions for prevention and mitigation. The research will help in minimizing OOS work in construction projects, which will yield enhanced productivity, reduced cost and incidence of schedule overruns, and a better overall contracting environment.