Armington's insight that imports and domestically produced goods were imperfect substitutes has unleashed extensive estimates of the associated trade elasticity, primarily for developed countries. This notion of product differentiation, which extends symmetrically to exports and domestic goods,...

The International Food Policy Research Institute’s International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) supports analysis of long-term challenges and opportunities for food, agriculture, and natural resources at global and regional scales. IMPACT is...

As crude oil prices reach new highs, there is renewed concern about how external shocks will affect growth and poverty in developing countries. This paper describes a macro-micro framework for examining the structural and distributional consequences of a significant external shock-an increase in...

In this paper, the authors describe South Africa's value added tax (VAT), showing that (1) the VAT is mildly regressive, and (2) it is an effective source of government revenue, compared with other tax instruments in South Africa. They evaluate the VAT in the context of other distortions in the...