An investigation of critical chain and lean project scheduling

Abstract

Critical chain and lean construction are two inspiring initiatives aiming at dramatically improving project performance through attacking the traditional management methods. The critical chain approach advocates improving throughputs to shorten task duration estimates and deploys various schedule buffers (i.e., project, feeding, resource, and capacity) to protect the project due date. The lean construction principles emphasize on eliminating waste by reducing non-value adding activities and managing hidden flows to improve the reliability of planning and production control. This paper investigates both practices and suggests that it is feasible, and necessary, to balance between aggressiveness (critical chain) and reliability (lean). A combination of critical chain and lean principles may provide benefits of both perspectives, with which critical chain is employed at relatively higher level to set up aggressive goals on task durations and deliveries of prerequisites, while lean works at low level to minimize the impact of flow uncertainties. An illustrative case study is provided to depict the effect of planning and control applying both the critical chain and the lean approaches.