In Six Sigma, what does "sigma" represent?

In Six Sigma, "sigma" refers to a measure of process variability and performance. Specifically, it represents the statistical term that quantifies the degree of variation in a process. The goal of Six Sigma is to minimize this variability and improve the overall quality of processes, products, and services. When the sigma level increases (moving closer to six sigma), it indicates that the process operates with fewer defects per million opportunities, thus leading to improved consistency and reliability.

Understanding sigma in this context is crucial because it helps organizations identify how much variation exists in their processes and guides them in implementing strategies to reduce this variability. This improvement ultimately leads to enhanced customer satisfaction, but the core definition of sigma itself is centered around process performance rather than customer perceptions or team dynamics.