Six Sigma
Six sigma is quality standard of just 3.4 defects per one million opportunities or 99.9996% perfect.
It is also an improvement methodology that emphasizes mathematical and statistical tools to improve the quality of processes that are already under control. Application follows a five-step process of define, measure, analyze, improve, and control often referred to as DMAIC.

Motorola conceived the technique in 1986 as a way to achieve the company’s improvement goals in manufacturing and support functions. The term refers to the number of standard deviations a point is away from the mean point in a bell curve. It often is represented as 6σ.
Many lean thinkers apply six sigma techniques to solve stubborn quality problems in value-adding processes that already are under control and where an analysis of the overall value-stream has eliminated nonvalue-adding processes.
Additional Resources on Six Sigma
- Jim Womack on how lean compares with Six Sigma, Re-engineering, TOC, TPM, etc., etc.
- What is the lean approach to quality – is that what six sigma is all about?
- From Staffs Conducting Programs to Line Managers Solving Problems
- Ask Art: The Benefits of Kaizen Learning vs. Traditional Problem-Solving
- The improvement journey of Dubai Police