Weighting for External Validity
NBER Working Paper No. 23826
---- Acknowledgments ----
Sophie Sun provided excellent research assistance. We thank Nick Bloom, Guido Imbens, Matthew Gentzkow, Peter Hull, Larry Katz, Ben Olken, Jesse Shapiro, Andrei Shleifer and participants in seminars at Brown University, Harvard University and University of Connecticut for helpful comments. Andrews gratefully acknowledges support from the Silverman (1978) Family Career Development chair at MIT, and from the National Science Foundation under grant number 1654234. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.