Impact of overtime on construction labor productivity

This article examines the impacts of overtime on construction labor productivity, and consequently costs, for mechanical and electrical contractors. Overtime in this research is defined as the hours worked beyond the typical 40-hours scheduled per week. The article begins by presenting the effects of overtime and providing a representative sampling of the available overtime literature. Data for the quantitative analysis was collected from 67 projects localed across the US by means of a questionnaire. Various statistical analysis techniques were performed to develop quantitative relationship curves, including the stepwise method, P-value tests, analysis of variance, and multiple regression. The results showed a one percent to 60 percent loss of productivity depending on the amount of overtime used and the type of construction performed. Case studies are presented to confirm the validation of the final regression model and also as examples of how to correctly use the model.