Aside from the colored band on a martial arts belt, the biggest difference in the Lean Six Sigma World, is that Green Belts get more training, understand more tools and techniques and can lead bigger projects than Yellow Belts. Yellow Belts receive training that provides the vocabulary of Lean Six Sigma, a basic understanding of the method and the most commonly used tools. With their overview of Lean Six Sigma, Yellow Belts become productive team members on process improvement teams led by Green Belts or Black Belts.
Green Belts, on the other hand, can be both team leads as well as team members. They are expected to complete an ongoing series of manageably-scoped projects as part of their work life. They can also participate as team members on projects run by Black Belts or even other Green Belts. What Green Belts and Yellow Belts have in common is that, unlike Black Belts, running Lean Six Sigma projects is not their only job. But it makes their jobs more enjoyable!