I read an article a few years ago about a study that showed that people who are not competent in a particular area of knowledge are not capable of recognizing competence in others. The article related primarily to business, explaining poor hiring decisions and other related problems. I saw it myself when a person who was considered by management to be an expert in technology was known to be incompetent by anyone who actually understood technology. Managment still relied upon him for his "expertise" when making one disastrous tech-related decision after another.
It also works when trying to get instruction when you are learning a new skill. How do you choose someone to teach you? How do you know competent instruction from incompetent instruction when you are not competent to judge the difference?
I did not learn to ski until I was in my 20's. I could barely afford the lift ticket, let alone instruction, so I relied on friends who seemed to know what they were doing, and I watched the experienced skers to learn good technique. In accordance with the research posted above, I managed to pick out really poor role models, and when I eventually started getting competent instruction, it took many, many years to overcome the bad habits I had acquired.
I did not get certified until I was in my 40's, and I soon found myself surrounded by experienced divers who were eager to give me advice. I also watched the processes followed by those around me who seemed to know what they were doing. Fortunately, I had already had my skiing experience, so I was very careful about accepting anything I heard or saw.
I have since had a lot of instruction from certified scuba instructors. I know that much--perhaps most--of the early advice I received from experienced divers was BS--and sometmes dangerous BS. Some of it could get one killed.
So, if I want to learn more about scuba, especially with skills that are life-threatening, how do I pick a competent Mentor?
Do I listen to a certified instuctor from any agency?
Or should I listen to someone who tells me he doesn't have any formal training but it doesn't matter because certifying agencies are a bunch of crap and his experience is better than the stuff all these agencies teach--"just trust me and put your life into my hands"?