Knowledge Base · Foundations
What is Six Sigma?
Six Sigma is a disciplined, data-driven method for eliminating defects and variability in a process. Its statistical goal is near perfection: 3.4 defects per million opportunities. Where Lean focuses on waste and speed, Six Sigma focuses on quality and consistency, using data to find what causes variation and control it.
The appendix glossary defines Six Sigma as a disciplined, data-driven approach and methodology for eliminating defects and variability in any process, with the goal of getting as close to perfection as possible, statistically 3.4 defects per million opportunities. It is used for critical, complex problems where quality and consistency matter most and data is available.
Chapter 1 explains it with a baker. If a customer buys a loaf on Monday and it is the best they have ever had, they expect the same quality on Friday. A burnt or undercooked Friday loaf costs more than one loaf; it damages trust. Six Sigma provides tools to understand what causes that variation, such as too much yeast, an oven that is too hot, or inconsistent kneading, and then to control those factors for a great result every time.
Training is organised in martial arts style belts. White Belts learn the basics and join local problem-solving teams, Yellow Belts help gather data on projects, Green Belts lead smaller projects, Black Belts lead significant projects and coach others, and Master Black Belts train the Black and Green Belts and help shape overall strategy.
Related questions
- What are the "Big Three" simple tools to start continuous improvement?
- What's the difference between Lean, Six Sigma, and continuous improvement?
- What is DMAIC, and when should I use it?
Source: the CI glossary in the book's Appendix.