On the Measurement of Product Variety in Trade
讨论了如何衡量贸易中的产品多样性，计算各国对美出口的多样性指数，并发现出口多样性越高的国家生产率也越高。
Product variety plays an important role in the theoretical work on monopolistic competition and trade, and recent empirical work has begun to quantify this for aggregate and disaggregate import demands. The authors discuss the measurement of product variety in trade, using a broad cross-section of industrial and developing countries and disaggregating across sectors. The authors calculate the export variety of countries in their sales to the United States, and relate the export variety indexes to country productivities. They confirm that countries with greater product variety in exports also have higher productivity. This may be due to their development of and access to these products.