Abstract for: Project Simulation: Rethinking the "Expected Completion Date".

System Dynamics simulation models have been used to assess disruption and delay in construction projects for almost fifty years. In these projects, the completion date is a key success factor, and thus the expected completion date (ECD) is a critical input to project management decisions. However, since system dynamics simulation models work at a much higher level of aggregation than what is used by project control systems, formulations for the ECD have been based on rough approximations, generally supported by a series of ad hoc “adjustments”. Our work in the field suggests a new approach based on the shape of the planned manpower curve, using data that is much closer to the actual inputs used by project control systems. A simple test model, simulating the perfect as-planned execution of a simple project, confirms both the biases introduced in the assessment of the ECD by conventional formulations, and the fact that the new formulation overcomes these. The new formulation has already been used in six delay and disruption claims and in one major research project, with exemplary results.