"You should believe me because I say so"? Really? I'm not saying you are or are not, but this line of justification is an insult to anyone who considers themselves rational thinkers.
I'd go so far as to say that it would be very difficult not to improve at something you were doing over a period of time.
I think the 'I NEED MORE NUMBERS' mentality of empiricism you're using here has neutralised the prospective utility of the intuition of experienced teachers who would make effective consultants, if they ever come across something that works that they simply can't explain. Obviously, questioning their suggestions and looking for answers is the next step, but to insult their ability to think and view their opinions with derison? How are you helping anything talking that way?