I've been evaluating high school football players for nearly 30 years and I can tell you that there is only one thing for certain: Nobody has all the answers. You do the best you can, judging a prospect's talent by whatever system you believe works for you, and hope you get it right.
The truth is someone always sees something different in an athlete. One coach says he's great while another says he's average. One recruiting service ranks a player among the top 100 in the country while another service doesn't rank him among the top 150.
I believe the only way to do it is to see a player in person, watch him on film, talk to him and his coach, get the human effect and determine how big his heart is.