I have made it a hobby, and thoroughly enjoy driving master black belts absolutely bonkers. It's part of my inner geek that no one who meets me would even think exists. It's a good thing, and bear in mind that without improvement, disorder will occur sooner rather than later. Loosely, and analogically, the second law of thermodynamics can be said to apply. As with martial arts, certain belt colors are given to equate to levels of competence; green is one of them. Yes, 6 sigma can be used to increase profit as well as improving overall efficiency in a process through the use of data. Can this be useful for determining the capability of a population of dog trainers? Maybe yes, and maybe no, but stick a distribution chart in front of me and first place I go is in the direction I went.