第八章 税收的代价,Chapter 8 The Costs of Taxation,在本章中，你将,考察税收如何减少消费者和生产者剩余 了解税收无谓损失的意义和原因 考虑为什么一些税收的无谓损失大于另一些税收 考察税收收入和无谓损失如何随税收的规模而变动,在实现这些目的后，你应该能,把税收楔子放到供求图中，并确定税收收入和消费者与生产者剩余 把税收楔子放到供求图中，并确定无谓损失的值 说明为什么供求和需求富有弹性比缺乏弹性时，一种既定的税收将引起更大的无谓损失 说明为什么某些极大的税收引起税收收入增加，但引起极大的无谓损失,Prologue,We began our study of taxes in Chapter 6. There we saw how a tax on a good affects its price and the quantity sold and how the forces of supply and demand divide the burden of a tax between buyers and sellers. In this chapter we extend this analysis and look at how taxes affect welfare, the economic well-being of participants in a market. The effects of taxes on welfare might at first seem obvious. The government enacts taxes to raise revenue, and that revenue must come out of someones pocket. As we saw in Chapter 6, both buyers and sellers are worse off when a good is taxed: A tax raises the price buyers pay and lowers the price sellers receive. Yet to understand fully how taxes affect economic well-being, we must compare the reduced welfare of buyers and sellers to the amount of revenue the government raises. The tools of consumer and producer surplus allow us to make this comparison. The analysis will show that the costs of taxes to buyers and sellers exceeds the revenue raised by the government.,8.1 税收的无谓损失 THE DEADWEIGHT LOSS OF TAXATION,How do taxes affect the economic well-being of market participants? It does not matter whether a tax on a good is levied on buyers or sellers of the goodthe price paid by buyers rises, and the price received by sellers falls.,The Effects of a Tax.,Price,0,Quantity,Supply,Demand,8.1.1 税收如何影响市场参与者 How do taxes affect the market participants?,现在我们用福利经济学的工具来衡量对一种物品征税的收益与损失。为了这样做，我们必须考虑税收如何影响买者、卖者以及政府。 市场上买者得到的收益用消费者剩余(买者愿意为某物品支付的量减去他们实际支付的量)来衡量； 市场上卖者得到的收益用生产者剩余（卖者为一种物品得到的量减去其成本）来衡量； 政府的衡量指标是什么呢？税收收入,Tax Revenue,T = the size of the tax,Q = the quantity of the good sold,TQ = the governments tax revenue,Tax Revenue.,Price,0,Quantity,Quantity without tax,Supply,Demand,Price sellers receive,Quantity with tax,Price buyers pay,8.1.1 税收如何影响市场参与者 How do taxes affect the market participants?,我们考虑3个问题： 没有税收时政府收入及福利情况如何？ 2. 征收税收之后的社会福利是多少？ 3. 福利的变动情况是什么样的？,How a Tax Affects Welfare.,Quantity,0,Price,Demand,Supply,Q1,Q2,Tax reduces consumer surplus by (B+C) and producer surplus by (D+E),Tax revenue = (B+D),Deadweight Loss = (C+E),Changes in Welfare from a Tax,Without Tax,With Tax,Change,Consumer Surplus,A + B + C,A,- (B + C),Producer Surplus,D + E + F,F,- (D + E),Tax Revenue,none,B + D,+ (B + D),Total Surplus,A + B + C + D + E + F,A + B + D + F,- (C + E ),The area C+E shows the fall in total surplus and is the deadweight loss of the tax. 买者和卖者由税收受到的损失大于政府收入的增加。税收引起的总剩余减少被称为无谓损失，面积CE衡量无谓损失的规模。,How a Tax Affects Welfare,The change in total welfare includes: The change in consumer surplus, The change in producer surplus, The change in tax revenue. The losses to buyers and sellers exceed the revenue raised by the government. This fall in total surplus is called the deadweight loss.,思考：为什么税收会引起无谓损失？,在第七章中我们说明了，市场通常可以有效地配置稀缺资源。这就是说，供求均衡使市场上买者和卖者的总剩余最大化。但是，当税收提高了买者的价格而降低了卖者的价格时，它对买者的激励是比没有税收时少消费，而对卖者的激励是比没有税收时少生产。当买者和卖者对这些激励做出反应时，市场规模缩小到其最优水平之下。因此，由于税收扭曲了激励，就引起市场资源配置无效率。,8.1.2 无谓损失与贸易的好处 DEADWEIGHT LOSSES AND THE GAINS FROM TRADE,Taxes cause deadweight losses because they prevent buyers and sellers from realizing some of the gains from trade.,The Deadweight Loss.,Quantity,0,Price,Demand,Supply,Q1,PB,Price = P1 without tax,PS,Q2,无谓损失就是由于税收阻止了这些互利的贸易而引起的剩余损失。,8. 2 无谓损失的决定因素 Determinants of Deadweight Loss,What determines whether the deadweight loss from a tax is large or small? The magnitude of the deadweight loss depends on how much the quantity supplied and quantity demanded respond to changes in the price. That, in turn, depends on the price elasticities of supply and demand.,Tax Distortions and Elasticities.,Quantity,Price,Demand,Supply,0,(a) Inelastic Supply,Tax Distortions and Elasticities.,Quantity,Price,Demand,Supply,0,(b) Elastic Supply,Tax Distortions and Elasticities.,Quantity,Price,Demand,Supply,0,(c) Inelastic Demand,Tax Distortions and Elasticities.,Quantity,Price,Demand,Supply,0,(d) Elastic Demand,Determinants of Deadweight Loss,The greater the elasticities of demand and supply: the larger will be the decline in equilibrium quantity and, the greater the deadweight loss of a tax.,对上述结论的一点解释：,从这个图中所得出的结论很容易解释。税收造成无谓损失，是因为它使买者和卖者改变自己的行为。税收提高了买者支付的价格，因此他们的消费少了。同时，税收降低了卖者得到的价格，因此他们的生产少了。由于行为的这些变动，市场规模缩小到最优水平之下。供给和需求弹性衡量买者和卖者对价格变动的反应程度，从而决定了税收扭曲会使市场结果有多大变动。因此，供给和需求弹性越大，税收的无谓损失也就越大。,案例1：对劳动征税的无谓损失,劳动税对劳动市场结果的扭曲有多大呢？经济学家关于劳动税的无谓损失大还是小的看法并不一致。这种不一致产生于关于劳动供给弹性的不同观点。,劳动是否具有供给弹性？,那些认为劳动税并没有严重扭曲的经济学家相信，劳动供给是相当缺乏弹性的。他们说，无论工资如何，许多人都要从事全职工作。如果是这样的话，劳动供给曲线几乎是垂直的，劳动税造成无谓损失小。 那些认为劳动税引起严重扭曲的经济学家相信，劳动供给是较为富有弹性的。他们承认，某些工人群体的劳动可能缺乏弹性，但认为，许多其他群体对激励反应较大。书上有一些例子：,The Deadw