Practical Considerations for Questionable IVs

This paper examines a number of techniques which allow for the construction of bounds estimates based on instrumental variables (IVs), even when the instruments are not valid. The plausexog and imperfectiv commands are introduced, which implement methods described by Conley et al. (2012) and Nevo and Rosen (2012b) in Stata. The performance of these bounds under a range of circumstances is examined, leading to a number of practical results related to the informativeness of the bounds in different circumstances.