Six Sigma is a data-driven methodology for improving processes by reducing defects to 3.4 per million opportunities through the DMAIC cycle of Define, Measure, Analyze, Improve, and Control. It aims to help companies achieve near-perfect product and service quality, increase profits, and improve customer satisfaction. The document outlines the roles and responsibilities of various Six Sigma positions like Master Black Belts, Black Belts, Green Belts and Champions and provides examples of how HR can contribute to and benefit from Six Sigma projects.