Lean Construction (LC) has changed the way construction projects are designed and constructed. The fundamental principles of LC, basic practices and common vocabulary, while well established continue to evolve. New developments call for new theories to describe and explain what works and why. This paper explores the difference between "Traditional CPM based Management" (TM) and LC in three domains: "operating system" from an activity based to flow based, "commercial terms" from transactional to relational contracts, and "organization" (authorities and communication protocols) from command and control to distributed and collaborative. These advances raise new questions and directions for research and create opportunities for new practices.
Lean construction, Theory, Contract, Uncertainty, Organization, Collaboration, IPD.