A Six Sigma Black Belt allocates 100% effort to a project, and they often train green belts while managing Six Sigma projects.
Six Sigma Master Black Belts are 100% allocated. Six Sigma Master Black Belts often mentor aspiring black belts. Learn more in this overview.
A Green Belt knows a fair amount about Six Sigma methodology, and can support a Black Belt in a major project or take on minor projects.
Six Sigma Belts loosely parallel American martial arts schools: Lighter belts are novices, black belts are experts.
Joseph M Juran was a quality luminary that focused on top management involvement, the quality trilogy, quality cost measurement, and Pareto analysis.