Clear definition of any new philosophy, tool or method applied in the management of projects is required for successful implementation. Distinguishing the traditional practice based on the Critical Path Method from new practices inspired on Lean Project Delivery is important to explain, understand and support its growing acceptance. Lean Construction developed from tools and techniques applied in the construction phase to a philosophy resting on firm conceptual foundations applied throughout the project life cycle. New terms, "Lean Project Management", "Lean Project Delivery" and "Integrated Project Delivery", have emerged but there is no specific accepted definition or clear distinction between these terms and other project delivery methods. Whatever delivery method is chosen, all projects have Commercial Terms, Organizations, and an "Operating System" and are shaped by the culture and technology. Based on literature review, this paper aims to clarify these terms and provide a structure for understanding how Lean Project Delivery is distinguished from "Traditional Practice" beginning with the underlying strategy for optimal performance, and by a focus on three domains: commercial terms, organization and operating system. The paper proposes that Traditional Practice provides a welldeveloped and coherent approach that differs from Lean Project Delivery, a not yet completely coherent approach.
Lean Project Delivery, Lean Project Management, Project Delivery.