Investigating Schedule Deviation in Construction Projects through Root Cause Analysis

In construction projects delays are not only disruptive but also expensive. Thus, the reasons for schedule deviation need to be identified. The delay factors determined in previous research were predominantly studied through surveys. In these studies, the participants were stakeholders in construction projects, and the reasons for schedule deviation were identified through their point of view. In addition, delay factors are typically considered individually and are presented at the same level. In reality, owing to the complex structure of construction projects and long execution time, non-conformance in schedules occurs by a chain of events. The aim of this research is to investigate the factors causing schedule deviation in construction projects and understand the cause-effect relationships between the events leading to delays. Among various techniques developed to root cause problems, fault tree analysis (FTA) is an established tool. FTA looks deeply into the chain of events leading to a problem to identify its primary cause. FTA was applied to a modular construction project that experienced significant delays. The analysis identified multiple delay factors, and showed how they are linked from the primary causes to the ultimate event. The root of most delays was traced to the inexperience of the project stakeholders.