Comprehensive Analysis of Factors Associated with Out-of-Sequence Construction

Abstract

Out-of-sequence work (OOS) is an activity or series of activities that were not performed according to baseline planned logical productive sequencing. Since OOS significantly weakens project performance, this paper pinpoints the factors that should be addressed to help mitigate it. Using an extensive project-based survey, 42 projects were statistically investigated. Projects with inadequate coordination among different parties were shown to suffer from significant OOS. Lack of owner participation and engineering support during construction were main causes of OOS, whereas implementing constructability and alignment processes helped mitigate it. Additionally, more collaborative project delivery systems better mitigated OOS compared to less collaborative ones. Change orders were highly associated with OOS. However, project complexity was not correlated with OOS, highlighting that all projects are prone to OOS regardless of complexity. Front-end planning, planning for start-up, three-dimensional modeling, and frequently updating project schedules helped mitigate OOS. In contrast, the excessive use of request-for-information forms and their prolonged processing time, unplanned overtime, trade stacking, and absenteeism were all directly associated with OOS. Professionals are advised to use the findings presented in this paper to help mitigate OOS, thus significantly improving project performance.