Modeling Productivity Loss Using System Dynamics to Understand Cumulative Impact

摘要

Identifying the cause and effect dynamics that result in productivity loss when scope changes are introduced on construction projects has been a topic of discussion for several years. In recent years, the issue of productivity disruption resulting in the phenomenon known as cumulative impact continues to remain prevalent because of the difficulty for contractors to identify, quantify, and show causation for impacts and damages. A project is a system requiring fully functioning processes and procedures, tools and resources, and when any of these aspects are not working efficiently, resulting especially from many unanticipated changes, a cascade of problems can occur. When changes are introduced during a construction project using the design-bid-build delivery method (DBB), cumulatively, these changes can dramatically affect project performance. Using system dynamic modelling, it is theorized that a construction contractor's ultimate productivity impacts can be calculated by simulating the primary causal influences and the resulting feedback loops. Identifying and quantifying the cause and effect relationships between changes in order to mitigate or avoid their impact is vitally important to the construction industry. This article was first presented as PM.1432 at the 2013 AACE International Annual Meeting in Washington, DC.