Six Sigma is a data-driven approach to improving processes by reducing variability. It aims for near perfect processes with fewer than 3.4 defects per million opportunities. The technical definition is achieving six standard deviations between the mean and the nearest specification limit. Six Sigma uses the DMAIC methodology of Define, Measure, Analyze, Improve, and Control and defines belts/roles such as Champions, Master Black Belts, Black Belts, Green Belts and Yellow Belts. Benefits include sustained success, improved customer satisfaction, and accelerated improvement.