What is Six Sigma? Six Sigma is a highly disciplined data driven approach to minimizing defects systematically. The Six Sigma approach was developed by Motorola, but most of the tools have been in use for many decades. The Six Sigma approach assists companies as they focus on improving processes to the point of “near perfection.” The idea behind Six Sigma is that defective parts in a given process are reduced to the level of 3.4 defects per million opportunities (DPMO). “Sigma” is the number of standard deviations from the process mean (average) within a standard bell curve, or process distribution. Most manufacturing processes tolerate three to four sigma operating levels, producing 6000 to 67,000 defects per million opportunities!