What is Six Sigma?

If you work for a large corporation, you've probably heard about Six Sigma and how it's going to dramatically improve the business. But what exactly is it, and what's all the fuss about?

Six Sigma Defined
There are many definitions of Six Sigma out there, but in its most basic terms, Six Sigma is a way to improve processes with the ultimate goal of eliminating defects and improving quality. A manufacturing process is anything that contributes to producing final product. A machine, for example, is considered a process. Businesses processes can also be improved with Six Sigma, with the goal of increasing efficiency and eliminating mistakes.

History
Six Sigma gets its name from the bell curve used in statistics. The capability of a process (its ability to produce products within control limits or specifications) is represented as a bell curve. A "Sigma" is one standard deviation away from the mean. When a process exhibits six sigmas (three above the mean and three below) then the defect rate is extremely low-- almost at zero. But you don't need to understand the statistics of Six Sigma to understand how it works. Just remember that Six Sigma involves measuring a process' capability using statistics. Let your company's statisticians and "black belts" worry about the math (more on black belts later).

Six Sigma was first used at General Electric (GE) in their manufacturing operations to improve product quality, reduce waste, and ultimately save money. Due to GE's success with Six Sigma, other manufacturers starting implementing Six Sigma programs. Today, companies across all industries are using Six Sigma to improve processes. Even financial services firms are implementing Six Sigma for their billing and accounting processes.

Methodology
Six Sigma is carried out through the DMAIC cycle: Define, Measure, Analyze, Improve, Control. These five steps are repeated over and over again until the process has reached Six Sigma in terms of its capability and defect rate.