PurposeThe purpose of the paper is to develop a method to integrate the schedule-based analysis with a productivity-based analysis to prove and support the result of the damages calculation.Design/methodology/approachIn this paper, a “cost and schedule impact integration” (CSI2) model is proposed to objectively show and estimate lost productivity due to changes in construction projects.FindingsA schedule-based analysis to include separate tracking of change order costs can be used to predict productivity due to the delay and disruption; changes in construction projects almost always result in delay and disruption. However, the schedule-based analysis needs to be integrated with a productivity-based analysis to prove and support the result of the damages calculation.Practical implicationsThe results of this study expand upon construction practices for proving and quantifying lost productivity due to changes in construction projects.Originality/valueThe contribution of the paper is summarized as the introduction of a “schedule impact analysis” into a “cost impact analysis” technique to assess the damages, as well as to demonstrate the labor productivity impact due to delay and disruption in construction projects.