Lean Six Sigma combined the two words of Lean and Six Sigma to one word. The Lean and the Six Sigma were originally different principles. The Lean principle came from TPS (Toyota Production System), the Six Sigma on the other hand came from the Quality Management System in Motorola. It’s no exaggeration to say that these two principles are completely different.
Lean is Eastern Principle
The purpose of Lean is to eliminate the wastes by focusing on quality, cost, delivery, morale and safety so that we increase the customer values. “Kaizen” is a good example to increase the values. The Lean also focus on developing people and culture of the organization by continuous improvement and education.
Toyota has developed the TPS (Toyota Production System) for many decades. Then in year 2000, J.P. Womack published the book called “Lean Thinking” based on his research in the TPS. The word “Lean” has widely spread since his publication.
In the Lean, the continuous process improvement by eliminating the wastes is a key to embed (or build) product quality. The continuous process improvement is very similar to the eastern philosophy such as Zen or the eastern medicine. It’s because the eastern medicine improves the human health as a total system by improving dietary life, balance of body and blood/energy circulation.
Six Sigma is Western Principle
The Six Sigma was developed by Motorola based on W. E. Deming’s Quality Management System. It improves the product quality by reducing variation and stabilizing the process. The Six Sigma has widely spread since GE implemented the Six Sigma in their entire organization.
The Six Sigma is good at the statistical data analysis and the statistical process control. It examines the samples from the process, and statistically analyzed them. If an issue is found, then the Six Sigma starts a project to solve the issue. The Six Sigma fixes an issue one by one.
The Six Sigma approach is very similar to the surgery in the western medicine which fixes a joint pain or a bleeding by a surgery or an injection. And the western medicine examines the human body with data before the operation.
I am not saying one is better or worse. Actually we need both. When bleeding we need an emergency treatment of the western approach, and when improving the health continuously, we need a balanced diet in the eastern approach.
Lean Six Sigma
Because of the necessary of both approaches, the Lean and the Six Sigma was combined to one by M. George and R. Lawrence in the book of “Lean Six Sigma: Combining Six Sigma with Lean Speed” in 2002. The better quality of product, the faster speed of delivery, the higher customer satisfaction and the higher employee development has become the purpose of Lean Six Sigma since then. This is the blending of two philosophies.
There is a derivative from the Six Sigma. It is DFSS (Design for Six Sigma). The DFSS was derived from Six Sigma to prevent an issue before happening. In other words, the Six Sigma is an approach for the existing process (or product) which has an issue, and the DFSS is an approach for a new process (or product) which needs to prevent an issue before happening.
Lean, Six Sigma and DFSS are the main problem-solving frameworks nowadays.
Such historical circumstance makes the Lean Six Sigma be difficult to understand for many people. To me, the Lean Six Sigma and the DFSS are like “Rock-Paper-Scissors”. What we need to do is to select a best framework to solve a particular problem. It is a game.