PT  - JOURNAL ARTICLE
AU  - Cruz, Luiz M.
AU  - Moreira, Marcelo J.
TI  - On the Validity of Econometric Techniques with Weak Instruments
AID  - 10.3368/jhr.40.2.393
DP  - 2005 Mar 31
TA  - Journal of Human Resources
PG  - 393--410
VI  - 40
IP  - 2
4099  - http://jhr.uwpress.org/content/40/2/393.short
4100  - http://jhr.uwpress.org/content/40/2/393.full
SO  - J Hum Resour2005 Mar 31; 40
AB  - We evaluate Angrist and Krueger (1991) and Bound, Jaeger, and Baker (1995) by constructing reliable confidence regions around the 2SLS and LIML estimators for returns-to-schooling regardless of the quality of the instruments. The results indicate that the returns-to-schooling were between 8 and 25 percent in 1970 and between 4 and 14 percent in 1980. Although the estimates are less accurate than previously thought, most specifications by Angrist and Krueger (1991) are informative for returns-to-schooling. In particular, concern about the reliability of the model with 178 instruments is unfounded despite the low first-stage F-statistic. Finally, we briefly discuss bias-adjustment of estimators and pretesting procedures as solutions to the weak-instrument problem.