"To study the effects of tariffs on gross domestic product (GDP), one needs import demand elasticities at the tariff line level that are consistent with GDP maximization. These do not exist. Kee, Nicita, and Olarreaga modify Kohli's (1991) GDP function approach to estimate demand elasticities...

"Feenstra and Kee study the link between export product variety and country productivity based on data from 34 industrial and developing countries, from 1982 to 1997. They measure export product variety by the share of U.S. imports on the set of goods exported by each sampled country relative to...