Professionals who follow Lean Six Sigma use the data-driven methodology to improve processes by eliminating defects, variations, and waste. They embrace the disciplined, data-driven approach using problem-solving tools, statistical methods, and advanced analytics. The Six Sigma belt levels and certifications are similar to those of martial arts. Globally recognized, they are awarded to practitioners based on their level of skill, experience, knowledge, and training in Lean Six Sigma principles. Here are the basic roles and responsibilities of each belt level.