A quality standard of just 3.4 defects per one million opportunities; 99.9996% perfect.
Six sigma methodologies emphasize 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 six sigma 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.