A similar study using the PLAN (the middle sibling in the
EXPLORE, PLAN, ACT trio of tests) scores of 10th graders to predict future AP test scores is "Using PLAN to Identify Student
Readiness for Rigorous Courses in High
School" http://www.act.org/research/policymakers/pdf/UsingPlan.pdf . Some gifted kids take the ACT for a talent search. Since PLAN scores can be used to predict ACT scores http://www.act.org/planstudent/score/actcomp.html , the reverse should also be true.

"To see what is in front of one's nose needs a constant struggle." - George Orwell