Simulation analysis of labor performance during overtime and impact on project duration

The objective of this research is to quantify the anticipated impact of labor productivity during scheduled overtime on total project duration. In order to meet this objective, a Monte Carlo simulation model of variability and continuous deterioration of labor productivity during scheduled overtime of labor productivity during scheduled overtime was developed. The pattern of the productivity decline was modeled by the productivity curves reported by Business Roundtable in 1974 which is considered the most comprehensive study of construction overtime and labor productivity. Also, the techniques of statistical inference were used to fit a theoretical distribution to the productivity data obtained from CII research published in 1994. After performing the hypothesis tests, the lognormal distribution was selected to represent variability of daily labor performance during scheduled overtime in this simulation model. This research shows that estimating the impact of working overtime on the project duration without considering labor productivity decline leads to overestimation of the effectiveness of working overtime. This research also demonstrates that simulation analysis of scheduled overtime provides a more in-depth analysis of the overall impact on project schedule. The simulation analysis allows a project manager to assess and analyze the effectiveness of working different overtime options and to choose the right overtime option providing required schedule acceleration.