Instrumental Variables: An Econometrician's Perspective
NBER Working Paper No. 19983
---- Acknowledgements -----
Financial support for this research was generously provided through NSF grants 0820361 and 0961707. I am grateful to Joshua Angrist who got me interested in these topics many years ago, and, over the years, has taught me much about the issues discussed in this manuscript, the editor of Statistical Science for suggesting this review, and three anonymous referees who wrote remarkably thoughtful reviews. The views expressed herein are those of the author and do not necessarily reflect the views of the National Bureau of Economic Research.