A Concordance Between Ten-Digit U.S. Harmonized System Codes and SIC/NAICS Product Classes and Industries

We thank Julie Linden of the Yale University Social Sciences Library for generous help in securing the publicly available U.S. trade data. We thank Kitjawat Tacharoen and Matt Flagge for research assistance. We thank Alvin Venning, Carol Ann Aristone, James Kristoff and Mendel Gayle of the U.S. Census Bureau for many enlightening conversations. Schott thanks the National Science Foundation (SES-0241474 and SES-0550190) for research support. The research in this paper was conducted while Pierce was at Georgetown University. Any opinions and conclusions expressed herein are those of the authors and do not necessarily represent the views of the U.S. Census Bureau, the National Science Foundation, or the National Bureau of Economic Research. The research in this paper does not use any confidential Census Bureau information.

• data appendix