Key points are not available for this paper at this time.
John Bound, David A. Jaeger, Regina M. Baker, Problems with Instrumental Variables Estimation When the Correlation Between the Instruments and the Endogeneous Explanatory Variable is Weak, Journal of the American Statistical Association, Vol. 90, No. 430 (Jun., 1995), pp. 443-450
Bound et al. (1995) studied this question.