Economic research study attempting to show what changes might occur in USA production, consumption and imports if the USA were to grant preferential tariffs to developing countries on each of 160 commodity groups - comprises analyses of the probable effects of preferences and includes background material relating to the major existing nongeneralized preferential trading systems and current international efforts to create a system of generalized preferences. References and statistical tables.

"In recent debates, trade preference erosion has been viewed by some as damaging to developing countries, and by others as insignificant, except in a few cases. But little data have been available to back either view. The objective of this paper is to improve our measures of the size, utilization, and value of all U.S. nonreciprocal trade preference programs in order to shed light on this debate. Highly disaggregated data are used to quantify the margins, coverage, utilization, and value of agricultural and nonagricultural tariff preferences for all beneficiary countries in the U.S. regional programs and in the Generalized System of Preferences. Results show that U.S. regional tariff preference programs are generally characterized by high coverage of beneficiary countries' exports, high utilization by beneficiary countries, and low tariff preference margins (except on apparel). For 29 countries, the value of U.S. tariff preferences was 5 percent or more of 2003 dutiable exports to the United States, even after incorporating actual utilization. Most of this value is attributable to nonagricultural tariff preferences, and to apparel preferences in particular. These results suggest that preference erosion may be significant for more countries than many had thought."--World Bank web site.

The proliferation of preferential trade liberalization over the last 20 years has raised the question of whether it slows down multilateral trade liberalization. Recent theoretical and empirical evidence indicates this is the case even for unilateral preferences that developed countries provide to small and poor countries but there is no estimate of the resulting welfare costs. To avoid this stumbling block effect we suggest replacing unilateral preferences by a fixed import subsidy. We argue that this scheme would reduce the drag of preferences on multilateral liberalization and generate a Pareto improvement. More importantly, we provide the first estimates of the welfare cost of preferential liberalization as a stumbling block to multilateral liberalization. By combining recent estimates of the stumbling block effect of preferences with data for 170 countries and over 5,000 products we calculate the welfare effects of the United States, European Union and Japan switching from unilateral preferences to Least Developed Countries to the import subsidy scheme. Even in a model with no dynamic gains to trade we find that the switch produces an annual net welfare gain for the 170 countries ($4,354 million) and for each group: the United States, European Union and Japan ($2,934 million), Least Developed Countries ($520 million) and the rest of the world ($900 million).