Six Sigma is organized similarly to martial arts. Different levels are referenced by different belts, as in Judo. Practitioners range from Green Belts to Champions. The most common are White, Yellow, Green, Black, and Master Black Belts, although there are also options specific to healthcare and data analytics, to name a few. Six Sigma is certified by several universities and other bodies, and ASQ or IASSC are among the most recognized credentialing bodies, although there is no official certification body. Many organizations offer their own version of Six Sigma certification, and there are versions tailored to specific priorities, including the popular Lean Six Sigma.