Identification and quantification of non-value-adding effort from errors and changes in design and construction projects

In a design and construction project, non-value-adding effort (NVAE; also called non-value-adding activities) is wasted effort that could have been avoided if the project had been more carefully planned, executed, monitored, and controlled. NVAE is considered the main contributor to schedule delays and cost overruns in design and construction projects. Microlevel analyses such as work sampling and resource balance charts have been applied extensively to identify and minimize NVAE. These methods can pinpoint unnecessary steps in a highly repetitive construction activity and are most effective when analyzing activities with low performance variation in each cycle. However, microlevel analyses lack the capabilities to deal with errors and changes that usually result in significant performance variations, although they are a major trigger of NVAE in design and construction projects. To address this deficiency, this paper outlines the development of a system dynamics-based model for analysis on a macrolevel. The model's application to a bridge project in Massachusetts revealed that it can effectively identify and quantify NVAE particularly triggered by errors and changes, and can capture the propagation of NVAE between interrelated activities. On the basis of results, this paper concluded that the developed model can be utilized as a management tool to bring a more comprehensive understanding of NVAE in design and construction projects, which in turn can lead to a greater reduction in NVAE.