Koskela’s (1992) report explored the causation between the adoption of a specific production theory (i.e., the conversion model of production) and waste that stems from implementing that theory on complex projects. He suggested that project complexity results from: (1) a peculiarity of construction being rooted in the ground, namely ‘site production’, which requires that the flow of teams is coordinated and (2) the lack of consideration of this flow dimension in the conversion model of production that prevails in construction project management practice. He also highlighted that value delivery tends to be overlooked in the conversion model. Koskela’s (2000) dissertation further explored project complexity from a structural perspective, where project structural complexity refers to the interdependences between the multiple elements of the project domains (i.e., product design, engineering, installation, use).

This chapter builds on Koskela’s work by offering a framework to support the idea that Lean thinking offers a comprehensive approach to manage project complexity. This framework integrates the Lean Project Delivery SystemTM (LPDS) with a Multi-Domain-Matrix (MDM) as a means to visualise and model structural complexity on projects.

To deliver proof-of-concept, the framework was tested on a facility plant upgrade project delivered through a design-bid-build process. The framework was applied to the cooling tower selection, which was a project breakdown. It helped those involved gain a better understanding of the causes of the breakdown. It pointed out that traditional Project Management (PM) methods encourage project teams to focus on contract deliverables (e.g., programming documents, design drawings, shop drawings, installation milestones) rather than to collaboratively manage the project’s structural complexity. This understanding led to a new approach to cooling tower selection based on Lean Construction (LC) principles and methods, which might alleviate the burden of managing project complexity.

While project complexity has been addressed explicitly by some LC researchers to date, it is a topic worth further investigation.