Six Sigma Principles

By Craig Gygi, Neil DeCarlo, and Bruce Williams

Part of the Six Sigma For Dummies Cheat Sheet

Six Sigma is based on a handful of basic principles, and these principles create the entire Six Sigma arrangement. Here are Six Sigma's fundamental principles:

Y = f(X) + å: All outcomes and results (the Y) are determined by inputs (the Xs) with some degree of uncertainty (å).
To change or improve results (the Y), you have to focus on the inputs (the Xs), modify them, and control them.
Variation is everywhere, and it degrades consistent, good performance. Your job is to find it and minimize it!
Valid measurements and data are required foundations for consistent, breakthrough improvement.
Only a critical few inputs have significant effect on the output. Concentrate on the critical few.