Many industries are geographically concentrated. Many mechanisms that could account for such agglomeration have been proposed. We note that these theories make different predictions about which pairs of industries should be coagglomerated. We discuss the measurement of coagglomeration and use...

This paper examines home bias in U.S. domestic trade in 1949 and 2007. We use a unique data set of 1949 carload waybill statistics produced by the Interstate Commerce Commission, and 2007 Commodity Flow Survey data. The results show that home bias was considerably smaller in 1949 than in 2007...