Key points are not available for this paper at this time.
Joshua D. Angrist, Alan B. Krueger, Split-Sample Instrumental Variables Estimates of the Return to Schooling, Journal of Business & Economic Statistics, Vol. 13, No. 2, JBES Symposium on Program and Policy Evaluation (Apr., 1995), pp. 225-235
Angrist et al. (1995) studied this question.