United States demand for coffee imports
研究了美国对不同类型咖啡的进口需求，发现五种咖啡之间存在显著的互补性，且偏好模式在不同模型设定下高度一致。
The United States - one of the world's largest coffee importers - imports coffee beans from a variety of different countries. These countries are aggregated into five groups representing five broadly defined types of coffee. Imports of the five coffees over time are examined to determine price, expenditure and substitution elasticities. These elasticities reflect preferences as well a technical relationships in the form of blending recipes. The lower the degree of substitutability between the different types of coffee, the more inelastic the demand from the United States facing groups of exporting countries. The results suggest rigidities in United States imports of coffee of different types. These rigidities are evidenced by substantial complementarity among the five coffee types. Preference patterns are very similar across a wide range of model specifications. There are differences in expenditure elasticities for different types of coffee in the United States.