The Six Sigma methodology is a structured approach to problem-solving using data to make decisions using the DMAIC project flow: define, measure, analyze, improve and control. The different levels of training are classified by a series of belts, similar to martial arts: yellow, green, black and master black belt.
Yellow belts are executive champions who have attended a one-day overview of Six Sigma and DMAIC. The champions select projects for black belts and their teams to work on based on a company's goals.
These apprentice problem solvers spend a week in training and require a resolved project before certification. They also serve as data collectors for black belts.
Black belts attend an additional five weeks of training above the green belts, with added detail in experimental design. They will coach green belts through the more difficult parts of projects. Black belts are the most common certification and are considered the primary problem-solvers in a Six Sigma-driven company.
Master Black Belts
The master black belts are black belts with train-the-trainer training and even more in-depth experimental design work in their six weeks of class. Master black belts coach and certify all other belts, and are responsible for curriculum content and helping in project selection, based on close interaction with executive yellow belts.
Where to Get Certified
Although most large companies have their own internal certification programs, there isn't a consistency among companies. The American Society of Quality's Certified Black Belt (and other belts) is fast becoming a standard. ASQ also offers belts and training in areas such as health care and service.