微观经济学原理 ch08.doc

Questions for review What happens to consumer and producer surplus when the sale of a good is taxed? How does the change in consumer and producer surplus compare to the tax revenue? Explain. 当对一种物品征税时，消费者和生产者剩余都会减少。 我们可以用税收前后的总福利来比较生产者剩余和消费者剩余变动与税收收入，看税收前的福利与税收后的福利谁大谁小。税收前的福利=生产者剩余+消费者剩余，税收后的福利=生产者剩余+消费者剩余+税收收入。税收前的福利大于税收后的福利，说明生产者剩余和消费者剩余的减少大于税收收入。反之，则小于。 Draw a supply-and-demand diagram with a tax on the sale of the good. Show the deadweight loss. Show the tax revenue. 如图8-1所示，对一种物品征税减少了消费者剩余（面积B+E表示减少量）和生产者剩余（面积C+F表示减少量）。生产者和消费者剩余的减少大于税收收入（用面积B+C表示），税收引起了无谓损失（用面积E+F表示）。 How do the elasticities of supply and demand affect the deadweight loss of a tax? Why do they have this effect? 供给与需求曲线的弹性越大，税收的无谓损失越大；供给与需求曲线的弹性越小，税收的无谓损失越小。因为供给和需求弹性衡量买者和卖者对价格变动的反应程度，决定了税收扭曲会使市场结果有多大变动。 What happens to the deadweight loss and tax revenue when a tax is increased? 当税收增加时，无谓损失增加，并且无谓损失的增加要快于税收规模的增加。税收增加时，税收收入先增加，然后随着税收规模越来越大，市场收缩非常之大，以至于税收收入开始减少。 Problems and applications Evaluate the following two statements. Do you agree? Why or why not? “If the government taxes land, wealthy landowners will pass the tax on to their poorer renters.” “If the government taxes apartment buildings, wealthy landlords will pass the tax on to their poorer renters.” Answer: 同意。因为佃户对土地的需求基本是无弹性的，而税收总是市场中弹性较小的一方承担的多。所以，地主可以把税收转嫁给贫穷的佃户。 部分同意。在短期内，对于公寓楼的需求基本是缺乏弹性的，因为寻找新住处需要一定时间。此时，房东会通过提高房租或减少对房屋的维修投入将税收转嫁给房客。但是，对公寓楼的需求在长期中是较富有弹性的，房客可以去选择更廉价的住处。因此，房东和房客将分担这项税收。 Evaluate the following two statements. Do you agree? Why or why not? “A tax that has no deadweight loss cannot raise any revenue for the government.” “A tax that raises no revenue for the government cannot have any deadweight loss.” Answer: 不同意。有些税收不会产生无谓损失，只会增加政府收入。例如庇古税，它是用于纠正负外部性的税收。征收庇古税使资源配置接近于社会最优，既增加了政府收入，又提高了经济福利。 不同意。除极个别情况外，税收都会引起市场规模的缩小，造成无谓损失。如果政府对某种物品的销售额全额征税，这个市场的需求和供给就会变成零，此时政府没有税收收入，但却带来极大的无谓损失，这个市场的买者和卖者无法进行互利的贸易了。 After economics class one day, your friend suggests that taxing food would be a good way to raise revenue because the dem