Lean construction

Lean construction is a combination of operational research and practical development in design and construction with an adaption of lean manufacturing principles and practices to the end-to-end design and construction process. Unlike manufacturing, construction is a project-based production process. Lean construction is concerned with the alignment and holistic pursuit of concurrent and continuous improvements in all dimensions of the built and natural environment: design, construction, activation, maintenance, salvaging, and recycling (Abdelhamid 2007, Abdelhamid et al. 2008). This approach tries to manage and improve construction processes with minimum cost and maximum value by considering customer needs (Koskela et al. 2002).'While the cost of steel and cement are making headlines, the less publicized failures in the management of construction projects can be disastrous. Listen carefully to the message in this comment. We are not talking about just materials, methods, equipment, or contract documents. We are talking about how we work to deliver successful capital projects and how we manage the costs of inefficiency.' The collaborative, commitment-based planning system that integrates should-can-will-did planning (pull planning, make-ready, look-ahead planning) with constraint analysis, weekly work planning based upon reliable promises, and learning based upon analysis of PPC (plan percent complete) and reasons for variance. Lean construction is a combination of operational research and practical development in design and construction with an adaption of lean manufacturing principles and practices to the end-to-end design and construction process. Unlike manufacturing, construction is a project-based production process. Lean construction is concerned with the alignment and holistic pursuit of concurrent and continuous improvements in all dimensions of the built and natural environment: design, construction, activation, maintenance, salvaging, and recycling (Abdelhamid 2007, Abdelhamid et al. 2008). This approach tries to manage and improve construction processes with minimum cost and maximum value by considering customer needs (Koskela et al. 2002). The term lean construction was coined by the International Group for Lean Construction in its first meeting in 1993 (Gleeson et al. 2007). Construction in Lean Construction refers to the entire industry and not the phase during which construction takes place. Thus, Lean Construction is for owners, architects, designers, engineers, constructors, suppliers & end users. Lauri Koskela, in 1992, challenged the construction management community to consider the inadequacies of the time-cost-quality tradeoff paradigm. Another paradigm-breaking anomaly was that observed by Ballard (1994), Ballard and Howell (1994a and 1994b), and Howell (1998). Analysis of project plan failures indicated that 'normally only about 50% of the tasks on weekly work plans are completed by the end of the plan week' and that constructors could mitigate most of the problems through 'active management of variability, starting with the structuring of the project (temporary production system) and continuing through its operation and improvement,' (Ballard and Howell 2003). Evidence from research and observations indicated that the conceptual models of Construction Management and the tools it utilizes (work breakdown structure, critical path method, and earned value management) fail to deliver projects 'on-time, at budget, and at desired quality' (Abdelhamid 2004). With recurring negative experiences on projects, evidenced by endemic quality problems and rising litigation, it became evident that the governing principles of construction management needed revisiting. One comment published by the CMAA, in its Sixth Annual Survey of Owners (2006), pointed to concern about work methods and the cost of waste: Koskela (2000) argued that the mismatch between the conceptual models and observed reality underscored the lack of robustness in the existing constructs and signaled the need for a theory of production in construction. Koskela then used the ideal production system embodied in the Toyota Production System to develop a more overarching production management paradigm for project-based production systems where production is conceptualized in three complementary ways, namely, as a Transformation (T), as a Flow (F), and as Value generation (V).