Key points are not available for this paper at this time.
Mary Ann Swiatek, Camilla Persson Benbow, A 10-Year Longitudinal Follow-up of Participants in a Fast-Paced Mathematics Course, Journal for Research in Mathematics Education, Vol. 22, No. 2 (Mar., 1991), pp. 138-150
Swiatek et al. (Fri,) studied this question.