Both the Toyota Production System (Lean) and Six Sigma approaches owe their origins to a common body of work. Statistical Process Control (SPC), developed by American engineer and statistician Walter A Shewart, is one of the foundations of lean. It is also the basis for much of the Six Sigma methodology. The other lean foundation, Total Quality Control, was developed by Dr. W. Edwards Deming and applied by him in both the United States and Japan.
These two founding themes were embraced by Taichi Ohno, who is broadly acknowledged as the father of the Toyota Production System. Shigeo Shingo—who is well known for taking concepts of zero defect production, Single Minute Exchange of Die (SMED) and Toyota Production System to a broader audience.
Excited by the simplicity and elegance of process control and the need to manage production efficiently, and driven by the need in postwar Japan to fully realize the “less is more” principle, Toyota developed TPS as a way to achieve previously unheard of levels of productivity, quality, and flexibility with minimal investment.
Aside from the shared history of both Lean and Six Sigma, both also share a common philosophy: Lean and Six Sigma both believe in systematically solving the problems that affect the customer.
The way Lean and Six Sigma happen in application is through the use the DMAIC and PDCA/A3 Framework, which I’ll discuss in the next series of posts.