This session will address the accepted methods of identifying and quantifying losses of labor productivity and attendant delays to the project schedule, using real world examples. We will discuss the necessity for contemporaneous labor productivity recognition, schedule monitoring and the need for detailed field record keeping that documents impacting events as they occur. Several well recognized methodologies for quantifying and presenting losses in labor productivity will be described, as well as a review of recent court and board of contract appeals cases on presenting loss of labor productivity claims.