One of the questions needing clarity is understanding why many (or most) kids at one point or another experience something bad such as a horrible Rebbe or the like and don’t go off the Derech just because of that while others do. There must be something deeper than just a bad experience or questions unanswered that are the root of the cause.
To be honest and don’t as of yet know what the common denominator is and I don’t think this survey has gotten to it yet as well. Perhaps we have some information that might help, but we’re not there yet.