Lean Design Process

Improper design in the construction industry leads to change orders, rework, decreased constructability, cost overruns, and delays, making it one of the biggest causes of waste. The writers aim to develop a lean design process to enhance design reliability by creating a learning environment using the design correctness ratio. Waste is first identified by analyzing the planning and design processes. A new design workflow is then proposed using lean concepts to smooth design work, reduce unnecessary design errors, and increase design reliability. The proposed process can provide team members with feedback on design status and thus allow for continuous improvement. The lean process is conceptualized using system dynamics to validate applicability. Analysis shows that the proposed lean design process can enhance design completeness and reliability, thus increasing design correctness. Waste due to improper design could be reduced accordingly. The proposed process is one of the first to apply the lean approach to construction-project design. © 2014 American Society of Civil Engineers.