[讨论]爱尔兰饥民只吃土豆（Giffen Goods）吗？

着么看,土豆是吉芬品,就必须是inferior Goods,并且可以被高级的替代,如果以上的成立,饥民就该另有更好的替代物,看起来当时更多物品是有,但因饥民为支付能力,等于没有,即使土豆飞张,估计价格可能没超过同期的高级替代品,饥民从支付上没有更多可选择,这样,土豆对饥民来说不是吉芬品,对有更好支付能力的是,如果说土豆是积分品,或者要先设定正常的购买能力高于土豆,并且表达达方必须有此支付能力,所以饥民没条件说土豆是吉芬品,只要不是当时的饥民,都可以说在当时正常支付情况下,土豆是吉芬品

以下是引用jianggenghua在2006-10-23 23:19:00的发言：

土豆不仅是吉芬品，还是必需品，所以，由于土豆价格的上升，为了能维持生命，就必须减少其他食品的消费，毕竟，相对于其他商品来讲，土豆还是最便宜的，所以才会出现价格上升而消费量上升的现象。

第二，吉芬品质是一定时间内的吉芬品，随着收入的增加，原先的吉芬品也会变成正常品。这和收入的多少有关。

应该说土豆因为是必需品才可能是吉芬品，这当中是有因果关系的。

words about this problem from Microeconomics and Behavior by Robert H.Frand:
Modern historians dispute whether the potato ever was really a Giffen food. Whatever the resolution of this dispute, the potato story does illustrate the characteristics that a Giffen good would logically have to possess. First, it would not only have to be inferior, but also have to occupy a large share of the consumer's budget. Otherwise, an increase in tits price would not create a significant reduction in real purchasing power. (Doubleing the price of keyrings,for example, does not amke anyone appreciably poorer.) The second characteristic required of a Giffen good is that it have a relatively small substitution effect, one small enough to be overwhelmed by the income effect.
In practice, it is extremely unlikely that a good will satisfy both properties required of a Giffen good. Most goods, after all, account for only a tiny share of the consumer's total expenditures. Moreover, as noted, the more broadly a good is defined, the less likely it is to be inferior. Finanlly, inferior goods by their very nature tend to be substitute ground sirloin for hamburge, for example, is precisely what makes hamburger tend to be an inferior good.
The Giffen good is an intriguing anomaly, chiefly useful for testing students' understanding of the subtleties of income and substitution effects....

[此贴子已经被作者于2006-10-26 17:52:32编辑过]

土豆？？？？？？？？？？

貌似吉芬物品是非常特殊的,生活中很少,不好研究啊