I think one issue with the colour approach is, that multiple dimensions of character traits are thrown into one pot (one colour) even though, they might be independent traits. Also, saying, someone is one/two/three colours is quite an all or nothing approach, that does not reflect reality, as character traits are non-binary (see for example the scientifically more grounded “Big Five”).
Over all, when a good salesman closes a deal, with the knowledge of this approach that you have been taught, it does not say, that the approach works. A good salesman uses common sense and experience in talking with people and of course adapts to the customer, but that does not mean, that he uses this special theory. (Maybe, you did perform bad, because you used the theory )
I would say, if we did a study with a control group, one group has been taught the theory, you have been taught, and the control group is not (but maybe, we tell them, take notice of the other person and try to adapt to their character), and if we notice, that the theory trained salesmen actually perform better, then we can say this framework is of any use. We still don’t know, of course, if not a different form of training could outperform this framework.
Until then, it is just anecdotal evidence.
Over all, when a good salesman closes a deal, with the knowledge of this approach that you have been taught, it does not say, that the approach works. A good salesman uses common sense and experience in talking with people and of course adapts to the customer, but that does not mean, that he uses this special theory. (Maybe, you did perform bad, because you used the theory )
I would say, if we did a study with a control group, one group has been taught the theory, you have been taught, and the control group is not (but maybe, we tell them, take notice of the other person and try to adapt to their character), and if we notice, that the theory trained salesmen actually perform better, then we can say this framework is of any use. We still don’t know, of course, if not a different form of training could outperform this framework. Until then, it is just anecdotal evidence.