This reminds me of the story of a scientist who won the Nobel Prize many years ago - believe it may have been physicist Richard Feynman. During the introduction speech, the emcee noted that Feynman's IQ was only 122. In intellectual circles, this is the football equivalent of a 2-3 star recruit, and Feynman's wife cringed at this perceived slight as her husband accepted his award. Later, in the taxi going back to their hotel, she asked if he was okay. His response? I just won the Nobel Prize, the highest recognition for scientific achievements, an award won by geniuses. I've joined the ranks of Einstein, Fermi and Schrodinger ... And I did that with a 122 IQ!
In the end, there is no crystal ball to predict effort. It is internal ... between you and you. So give me the kids who show up and make that extra effort. I think we've gotten a bunch this year already.