Aggregating from Micro to Macro Patterns of Trade

We are especially grateful to Ben Faber, Dave Donaldson, Rob Feenstra, Keith Head, Pete Klenow, Kalina Manova, Thierry Mayer, Marc Melitz, Gianmarco Ottaviano and Daniel Xu for helpful comments. We would also like to thank colleagues and seminar participants at Carnegie-Mellon, Chicago, Columbia, Duke, NBER, Princeton, Stanford and UC Berkeley for helpful comments. Thanks to Mark Greenan, Ildiko Magyari, Charly Porcher and Dyanne Vaught for outstanding research assistance. Redding and Weinstein thank Princeton and Columbia respectively for research support. Weinstein would also like to thank the NSF (Award 1127493) for generous financial support. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the U.S. Census Bureau or any organization to which the authors are affiliated. Results have been screened to insure that no confidential data are revealed. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.