Assessment of labor productivity in construction projects using system dynamic approach

Labor productivity is one of the most important factors in achieving project success at different stages of a project. in this research, a new method is presented to model labor productivity for different types of contractors based on system dynamic (sd) simulation. using cause and effect feedback loops, a qualitative model is constructed. the relationships between different parameters are then determined by expert's judgment and real data obtained from several real projects, and the quantitative model is built. the labor productivity is simulated by the proposed sd model, considering all affecting factors. for higher accuracy, the model is examined on two types of contractors and two models are constructed. the total productivity of each contractor is obtained, and the effect of different parameters on the labor productivity is investigated.