Transcript （一） Effects of a tariff

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
Jan.,2010
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.
120
110
100
Supply
90
80
70
60
50
40
30
International
price
20
10
Demand
0
0
10
20 30 40 50
60 70 80 90 100 110 120





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
120
110
100
Supply
90
80
70
60
50
40
Tariff
price
30
20
10
Demand
0
0
10
20 30 40 50
60 70 80 90 100 110 120


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.
P
S
Pt
a
P0
c
b
d
D
O
S1
S2
C2
C1
Q
1.
2.
3.
4.
5.
关税的价格效应：国内p
关税的消费效应: --(a+b+c+d)
关税的生产效应：+a
关税的税收效应：+c （ a和c也称为再
分配效应）
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.
2.
3.
4.
5.
6.
关税的价格效应：国内p
关税的消费效应: --(a+b+c+d)
关税的生产效应：+a
关税的税收效应：+(c+e)
关税的贸易条件效应：改善（出口价格不变
时）
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.
P
外国供给
P2
P0
P1
b+d
c
e
f
进口需求
O
M2
M1
Q 进口
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 importcompeting 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 weightedaverage tariff rate is to divide total tariff
revenue by the total value of imports.
Take the example,suppose this country import
product A ＄500 000， product B ＄ 200 000，
product C ＄100 000，then the weightedaverage tariff rate is:
(500 000×10%+200 000×15%+100 000×20%)/
(500 000+200 000+100 000)=100 000/800 000=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 Vj=$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Vj’
ERP
25%
8000(1+25%)=
10000
1500010000=
5000
(5000-2000)/
2000=150%
75%
8000(1+75%)=
14000
1500014000=
1000
(1000-2000)/
2000= -50%
(学生计算)
50%
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）