I are much too high.
Coached students are only slightly more likely to have large score gains than uncoached students.
The typical gain associated with coaching is 8 points for verbal and 18 points for math. Coaching seems to result in about one more verbal question correct for 25-30 hours of effort and one more math question correct for 8 or more hours of effort. I test takers of whom 427 were coached and 2,733 were uncoached. For purposes of this study, coaching is considered to include any and all activities conducted in special preparation programs offered to students outside their schools. ETS Research Report No.