Six Sigma certification is a method of denoting expertise in process improvement. While many companies and organizations offer certification courses, there isn't a standard certification body. As such, the standards for certification can vary.
Six Sigma originated in 1986 through Motorola as a method of standardization for how defects were counted. While this method was primarily developed for manufacturing processes, it has become popular in all forms of business. Besides Motorola, other major companies who use Six Sigma include General Electric and Citibank.
While the standards for certification vary, most certification programs entail a written test and the demonstration of the principles in a hands-on environment. As a means of indicating the different levels of proficiency, Six Sigma developed a belt system with three major levels: yellow, green and black. A black belt ranking indicates the individual who will lead most projects and interact with top executives. This individual will also oversee professionals with the lower belt rankings. During a project, yellow belts typically analyze and collect data. Green belts often act as middlemen between the yellow and black belts. They also carry out additional essential tasks.
Other Six Sigma certifications are offered that are more specific, such as the certifications for design and lean manufacturing. These certifications are considered to be green belt-level.