广东省省级精品课程 国 际 贸 易 Chapter 9: Tariff Effects 第九章 关税的经济效应 广东外语外贸大学 何元贵 教授

一、 Analysis of Tariff Effects （一） Effects of a tariff: small country In this market, the autarky equilibrium occurs a price of $50 and quantity of 50. If the international price is $20, the country will be an importer of the item. Domestic production will fall from 50 to 20. Domestic consumption will rise from 50 to 80. These changes generate imports of 60 units.

If a 50% ad valorem tariff is placed on imports, the domestic price rises from $20 (the international price) to the tariff price of $30. Domestic production increases from 20 to 30. Domestic consumption falls from 80 to 70. Imports fall to 40. The amount of tariff revenue is: $10 x 40 = $400

To show the welfare changes from the tariff the concepts of consumer and producer surplus must be considered. Consumer surplus is the difference between what consumers are willing to pay for a specific amount of a commodity and what they actually pay for it. Graphically, consumer surplus is the area under the demand curve and above the price paid on every unit purchased.

1. 关税的价格效应：国内 p 2. 关税的消费效应 : --(a+b+c+d) 3. 关税的生产效应： +a 4. 关税的税收效应： +c （ a 和 c 也称为再 分配效应） 5. 关税的净福利效应 : --(b+d) ，此部分属 于无谓损失（ deadweight loss ）。

The imposition of a tariff leaves a net welfare loss to society of the two triangular shaded regions( b&d). These regions are known as the deadweight loss of a tariff. b is production distortion, d is comsumption distortion.

（二） Effects of a tariff: large country The effects of a tariff on a large country differ from that in a small country because the imposition of a tariff results in a fall in import demand that lowers the international price. This is known is as the terms of trade effect.

（二） Effects of a tariff: large country 1. 关税的价格效应：国内 p 2. 关税的消费效应 : --(a+b+c+d) 3. 关税的生产效应： +a 4. 关税的税收效应： +(c+e) 5. 关税的贸易条件效应：改善（出口价格不变 时） 6. 关税的净福利效应 : e--(b+d)

This result arises as the improvement in the terms of trade more than offsets the potential deadweight loss of the tariff. Welfare lost: b+d Welfare gained: e

二、 Optimum tariff 1 、 Conception The previous example demonstrates that it is possible for the imposition of a tariff in a large county to improve societal welfare. An optimal tariff is the tariff rate that maximizes the benefit resulting from the imposition of a tariff. The gain comes from the improvement in the terms of trade.

2. More concern about the optimal tariff The existence of an optimum tariff appears to be a strong argument for interfering with free trade. It is important to note that the positive welfare gains exist only if no retaliation in other markets occurs following the imposition of a tariff.

三 、 The measure of tariff One method used to measure the degree of protectionism within an economy is the average tariff rate. Since tariffs generally reduce imports of foreign products, the higher the tariff, the greater the protection afforded to the country's import- competing industries. ( 一 ) Highness of tariff 1 ． Unweighted-average tariff rate Suppose a country have 3 kinds of import goods A 、 B 、 C ， their tarif rate are 10% ， 15% ， 20%.Then, their unweighted-average tariff rate is: (10%+15%+20%)/3=15%

The tariffs above are calculated as a simple average. To calculate this rate, one simply adds up all of the tariff rates and divides by the number of import categories. One problem with this method arises if a country has most of its trade in a few categories with zero tariffs, but has high tariffs in many import categories in which it would never find advantageous to import. In this case the average tariff may overstate the degree of protection in the economy.

2 ． Weighted-average tariff rate The standard way of calculating weighted- average tariff rate is to divide total tariff revenue by the total value of imports. Take the example,suppose this country import product A ＄ ， product B ＄ ， product C ＄ ， then the weighted- average tariff rate is: ( ×10% ×15% ×20%)/( )= / =0.125 ， that is 12.5%.

( 二 ) Nominal tariffs vs. effective protection 1 、 Concept The nominal tariff is the percentage increase in the price of the final commodity. The effective rate of protection is calculated on the increase in domestic value added offered by tariff protection. The effective rate of protection offers a better measure of the protection offered producers as it takes into account the cost to producers of tariffs on input markets.

2 、 How to get ERP? ERP=(V ’ -V)/Vx100% 。 ERP: 某行业的有效保护率； V 、 V ’ 分别表 示征收关税前后该行业 ( 或商品 ) 的国内生产 附加值。

3 、 Example & Calculation Suppose ： A car’s P=$10000 Middle cost =$8000 Added value before tariff V j =$2000 T=50% After tariff,the car’s P’= 10000(1+50%) =$15000

中间产 品的名 义税率 中间产品成本 最终产品增加 值变化 V j ’ ERP 25% 8000(1+25%)= = 5000 ( )/ 2000=150% 75% 8000(1+75%)= = 1000 ( )/ 2000= -50% 50% ( 学生计算 )

4. Conclusion As is seen, the effective level of protection may differ greatly from the rate of the nominal tariff. 当最终产品的名义税率大于中间产品名义税率时， 最终产品的有效保护率大于其名义税率。 当最终产品的名义税率小于中间产品名义税率时， 最终产品的有效保护率小于其名义税率 ( 负保护 ) 。 当最终产品和中间产品的名义税率相等时， 最终产品的有效保护率才和名义税率相等。

Review: 关税的经济效应 一、关税的效应 （一）小国模型 （二）大国模型 二、最优关税率 三、 关税的衡量 （一）关税的 “ 高度 ” （二）名义税率与有效保护率 （ Concept 、 Calculation 、 Conclusion ）