At the low end of the hierarchy of 6 σ methodology is the Six Sigma Yellow Belt. That's not to say that this role is unimportant to your improvement program, quite the opposite! The individuals in this role will play a vital part in many process improvement projects.
The six sigma yellow belt will be a critical resource to the team. Because it is simply not possible for a black or green belt to lead the improvement team and complete all of the project tasks, it becomes incumbent the project leader to rely upon the other team members... namely the yellow belts.
Training for this role is normally limited to 40 hours of instruction. Aside from learning the basics of the DMAIC process, these candidates will be well versed in improvement project tasks such as:
Of course, there are many more tools that are discussed within the 40 hours of training. Most training for this role is quite robust in its ability to show the basics of DMAIC and through the use of classroom activities, the use of the tools listed above in addition to simple analysis tools as well.
Don't think for one moment that these team members can't contribute in other ways. Because they should have intimate knowledge of the process to be improved, they should be promoting their improvement ideas to the team.
They'll also be of great assistance during the define phase of the project. They should be active team members when the project charter is completed, and throughout the other phases as well.