What Is Six Sigma? How Does It Tie Into The Best PMP Certification Training? The term Six Sigma originated from terminology associated with manufacturing, specifically terms associated with statistical modelling of manufacturing processes. The maturity of a manufacturing process can be described by a sigma rating indicating its yield, or the percentage of defect-free produsix sigma traiiningcts it creates. A six sigma process is one in which 99.99966% of the products manufactured are statistically expected to be free of defects (3.4 defects per million). Motorola set a goal of “six sigma” for all of its manufacturing operations, and this goal became a byword for the management and engineering practices used to achieve it.