摘要：The standard representative agent import demand system (hereafter called the standardapproach) is a popular way to model the aggregate demand for agricultural imports (Alston etal.). The Armington version or later versions (i.e. Rotterdam or LA-AIDS model) have beenused to estimate demand parameters useful in structuring government agricultural programs andcompeting strategically for global market share of goods and commodities. The key assumptionof the standard approach is that certain factors cause product differention by characteristicsunique to the country of origin. Paradoxically, nothing is done explicitly to include or explainthese differentiating characteristics in the model. Although the results can be interesting andintuitive, the obvious unanswered question remains "is the country of origin sufficient to explainwhy a product is more or less preferred."
