Identifying, Prioritizing, and Reducing Variation of Construction Related Tasks

In this research, variation is defined as the time difference between what was planned and what occurred in terms of task starting times and duration. Variation in construction tasks is important as it can impact overall productivity performance. Construction projects consist of a large number of interdependent tasks. When the starting time or duration of one task varies, it can affect other downstream tasks and result in disruptions to the schedule and/or decreased productivity. The construction process is complicated and involves numerous people with different levels of responsibility, which can make identifying the root causes of the variation difficult. The primary goals for this research include identifying, prioritizing, and reducing variation of construction tasks. Identification involved determining the most prevalent root causes of variation. Factor analysis was utilized to illustrate how those individual causes were interrelated with one another. A risk assessment matrix, commonly used in military planning, was used to quantify the associated frequency and severity of the causes of variation and prioritize which causes posed the greatest threat to project performance. Social network analysis was conducted to identify the underlying network of trades, along with the key members of the network. The results of the variation and social network analyses were combined to develop a decision support system to target variation for elimination. The analytical hierarch process (AHP) was used to support decision making when multiple and conflicting criteria were involved. Lastly, the research examined the feasibility of reducing variation by using the Last Planner System RTM. This research is important and valuable as it serves to address several gaps in the body of knowledge pertaining to variation associated with a construction project. Additionally, this research has a broader impact on the construction community. It provides a framework and repeatable associated analytical methods to identify, prioritize, and reduce variation on a construction project.