whereas high-import-penetration-ratio industries are concentrated in the Mid-Atlantic and New England regions.59 These concentrations imply that a downturn in a highly concentrated, import-sensitive industry can adversely affect the local economy and make individual adjustments to permanent job loss more difficult. Although import- and export-sensitive industries have both job losses and job gains, these general characteristics imply that trade-related job losses occur in separate labor markets from trade-related job gains. Previous research on job displacement reveals the importance of local labor markets.60 Measures of industry geographic concentration offer a way to further understand how local labor markets are influenced by trade flows and changes in trade policy.
The NBER Trade and Immigration data set contains information on imports, exports, and the value of shipments by four-digit 1972 SIC industry from 1958 to 1985. The basic classification system for imports and exports is by commodity type (using the Tariff Schedule of the U.S. Annotated (TSUSA). A concordance between TSUSA and SIC categories allows the development of an industry-based trade data set. The NBER data file is described in detail in Abowd ( 1991).
Import price data are available by four-digit SIC industry in U.S. Import and Export Price Indices, published by the U.S. Bureau of Labor Statistics. This variable is a quarterly, fixed-weight, Laspeyres price index based on a 1985 import market basket. These indices are described in more detail in U.S. Bureau of Labor Statistics ( 1992). They are based on a survey of actual transactions prices, and to the degree possible, they reflect c.i.f (cost, insurance, and freight) prices. Robert Z. Lawrence provided me with annual average tabulations for a collection of two-, three-, and four-digit SIC industries for the period 1980-91, and the NBER trade data were used to aggregate up to three-digit CIC. When aggregation was needed, the SIC indices were weighted by their relative shares in total imports. Quarterly____________________