System Dynamics as an Assistive Tool to Delay Analysis in Identifying Productivity Losses

Abstract

It is well established in the construction literature that change orders have negative impacts on project productivity. Such impacts have been measured through statistical models and data gathered from a large number of projects, which enables drawing conclusions on a broad level. However, there is a gap when it comes to modeling the relationships between change orders and construction productivity on the project level. This paper proposes a novel framework using system dynamics (SD) modeling to complement current delay analysis techniques in quantifying the impacts of owners’ change orders on project productivity. SD was used as the modeling tool for its ability in capturing rippled impacts and model complex systems. The research methodology (1) identifies the exogenous and endogenous parameters, (2) develops a dynamic hypothesis that guides model formulation, (3) develops the SD model along with its mathematical formulation, (4) runs verification tests, and (5) calibrates the model and tests it on a real case study. The developed model captures the typical construction cycle and can quantify the impact of each change order separately. In addition, after calibrating the model to any project, multiple what-if scenarios are conducted to provide further insights on allocating delay responsibilities. This model can identify the delays caused due to change orders that can be helpful for both contractors and owners to resolve the corresponding claims prior to escalation to disputes.