We do get the usual leaving patterns: after a few sessions, after six month, after a few years, and after getting shodan. While we, as instructors, can guess why this is happening, I am looking for hard evidence. Clearly, this will depend on too many things to be answered here. Thus what I am looking for is a method of finding out why people do not come back.
We tried questionnaires (no one would return them), phone conversations (too much pressure, thus no truth), and guess work (does not work).
Once we know why people are leaving, should be able to see what we are doing something wrong and what we could improve to retain members.