Stock, James H.; Andrews, Donald W. K. - 2021
This paper reviews recent developments in methods for dealing with weak instruments (IVs) in IV regression models. The … results under "many weak IV asymptotics," which are relevant when the number of IVs is large and the coefficients on the IVs … the asymptotic power envelope. This holds no matter what the relative magnitude of the IV strength to the number of IVs …