Effects of Change Orders on Cost Growth, Schedule Growth, and Construction Intensity of Large Highway Projects

Previous research have shown that change orders have a detrimental effect on cost growth and schedule growth of construction projects. These studies mainly concentrated on the number of change orders for building or maintenance projects. However, correlation of the number and change order growth with cost growth, schedule growth, and construction intensity of new highway projects has not been studied. This study collected data from 185 projects from the state of Texas, whose costs amounted to more than $10M. The results showed that the average change order growth for these projects was 7.0%, and also found a significant positive correlation in change order growth with cost growth and schedule growth of these projects. The correlation coefficients of change order growth with cost growth and schedule growth were found to be 0.57 and 0.44, respectively. When the projects were divided into two groups based on the change order growth, the results showed that the cost growth and schedule growth significantly increased as the change order growth increased to greater than 5%. The number of change orders were significantly and positively correlated with cost growth (0.23), schedule growth (0.30), and construction intensity (0.46). When the number of change orders increased by more than 20, then the cost and schedule growth increased significantly. It is recommended that Texas Department of Transportation engineers use an effective change management process to control the change orders in their highway projects so that cost and schedule overruns could be minimized. (C) 2018 American Society of Civil Engineers.