How Reliable are Simple, Single Equation Specifications of Import Demand?
检验了五个国家（加拿大、德国、日本、英国、美国）的九种进口需求模型，发现包含滞后因变量的动态模型表现较好，而简单模型和Almon滞后模型效果不佳。
This paper examines nine models of aggregate import demand for each of five countries (Canada, Germany, Japan, United Kingdom, and United States) in an attempt to determine which of the frequently used single equation models of import demand are appropriate. An appropriate model is defined as one which generates unbiased (or at least consistent) and efficient elasticity estimates. While models without lagged adjustments and Almon lag models perform rather poorly according to these criteria, models including dynamic behavior through lagged values of the dependent variable are frequently accepted. Results are reported regarding functional form, measures of variables, and structural shift. ECONOMISTS have devoted considerable attention to the estimation of aggregate import demand elasticities because of their importance in trade theory. The simplest procedure for estimating these elasticities which is consistent with economic theory is to assume that the elasticity of supply of imports is infinitely elastic and to estimate'