NBER Working Paper No. 26584
---- Acknowledgments ----
Many thanks to Ray Han and Shinnosuke Kikuchi for outstanding research assistance. Thanks also go to Alberto Abadie, Matias Cattaneo, Chris Hansen, Peter Hull, Guido Imbens, Simon Lee, Whitney Newey, Jose Olea, Parag Pathak, Bruce Sacerdote, Bernard Salanie, Stefan Wager, Chris Walters, and seminar participants at Columbia for helpful discussions and comments. They are not to blame for any of our mistakes or conclusions. This paper is dedicated to the memory of Alan Krueger. We would have liked to have his comments. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.