Lean, Six Sigma and Kaizen: Continuous Improvement Explained

Lean, Six Sigma and Kaizen get used interchangeably, but they solve different problems.

Lean: remove waste

Lean, born at Toyota, is about maximising customer value while eliminating waste — anything the customer would not pay for. Overproduction, waiting, excess inventory and unnecessary movement are all targets.

Six Sigma: reduce variation

Six Sigma attacks a different enemy: variation. Using the DMAIC cycle (Define, Measure, Analyse, Improve, Control) and statistical tools, it drives defects down to near zero. Where Lean is about speed and flow, Six Sigma is about consistency and quality.

Kaizen: the culture underneath

Kaizen means “change for better” — a culture of small, continuous improvements made by everyone, every day. It is less a toolkit than a mindset that makes Lean and Six Sigma sustainable.

How they fit

Many organisations run “Lean Six Sigma” — Lean to speed up flow, Six Sigma to lock in quality — on a foundation of Kaizen culture. Supporting tools include the Five Whys and the Ishikawa (fishbone) diagram for root-cause analysis. Explore them in the Operations library.