Consumers,
Producers, and the
Efficiency of Markets
消费者、生产者
与市场效率
Chapter 7
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Revisiting the Market Equilibrium
Do the equilibrium price and
quantity maximize the total
welfare of buyers and sellers?
u Market equilibrium reflects the way
markets allocate scarce resources.
u Whether the market allocation is
desirable is determined by welfare
economics.
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回顾市场均衡
市场均衡价格和数量能否使买者和
卖者的总利益最大化？
u市场均衡反映了市场配置稀缺资源的方式。
u 市场配置资源是否合意可以根据福利经济学
理论判定。
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Welfare Economics
Welfare economics is the study of
how the allocation of resources
affects economic well-being.
福利经济学——研究资源配置如何影
响经济福利 。
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Welfare Economics 福利经济学
Equilibrium in the market results in
maximum benefits, and therefore
maximum total welfare for both the
consumers and the producers of the
product.
市场均衡使利益最大化，即使产品的
消费者和生产者的总利益最大化。
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Welfare Economics 福利经济学
u Consumer surplus measures economic
welfare from the buyer’s side.
消费者剩余从消费者角度衡量经济福利。
u Producer surplus measures economic
welfare from the seller’s side.
生产者剩余从生产者角度衡量经济福利。
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Consumer Surplus 消费者剩余
u Willingness to pay is the maximum
price that a buyer is willing and able to
pay for a good.
支付意愿——买者为某种物品愿意和能
够支付的最高价格。
u It measures how much the buyer values
the good or service.
它衡量买者对物品的评价是多少。
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Consumer Surplus 消费者剩余
Consumer surplus is the amount a
buyer is willing to pay for a good
minus the amount the buyer actually
pays for it.
消费者剩余 ——买者支付意愿减去
买者的实际支付量。
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Four Possible Buyers’ Willingness to Pay...
四个可能买者的支付意愿…
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Consumer Surplus 消费者剩余
The market demand curve depicts
the various quantities that buyers
would be willing and able to
purchase at different prices.
市场需求曲线表示在不同价格水平
下，买者愿意和能够购买的数量。
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The Demand Schedule and the
Demand Curve
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需求表与需求曲线
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Figure 1 The Demand Schedule and
the Demand Curve
Price of
Album
50
70
80
0
$100
1 2 3 4 Quantity of
Albums
John’s willingness to pay
Paul’s willingness to pay
George’s willingness to pay
Ringo’s willingness to pay
Demand
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图1. 需求表与需求曲线
专辑的
价格
50
70
80
0
$100
1 2 3 4 专辑的数量
约翰的支付意愿
保罗的支付意愿
乔治的支付意愿
林格的支付意愿
需求
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Measuring Consumer Surplus with
the Demand Curve...
Price of
Album
50
70
80
0
$100
1 2 3 4 Quantity of
Albums
Demand
John’s consumer surplus ($20)
Price = $80
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用需求曲线衡量消费者剩余...
专辑的
价格
50
70
80
0
$100
1 2 3 4 专辑的数量
需求
约翰的消费者剩余（20美元）
价格 = 80美元
Figure 2 Measuring Consumer Surplus with
the Demand Curve
(b) Price = $70
Price of
Album
50
70
80
0
$100
Demand
1 2 3 4
Total
consumer
surplus ($40)
Quantity of
Albums
John’s consumer surplus ($30)
Paul’s consumer
surplus ($10)
图2. 用需求曲线衡量消费者剩余
(b) 价格 = 70美元
专辑的
价格
50
70
80
0
$100
需求
1 2 3 4
总消费者剩余
(40美元)
专辑的数量
约翰的消费者剩余 (30美元)’
保罗的消费者
剩余 (10美元)
’
Figure 3 How the Price Affects
Consumer Surplus
Consumer
surplus
Quantity
(a) Consumer Surplus at Price P
Price
0
Demand
P1
Q1
B
A
C
图3. 价格如何影响消费者剩余
消费者剩余
数量
(a)价格
在
P
价格
0
需求
P1
Q1
B
A
C
时的消费者剩余
Figure 3 How the Price Affects
Consumer Surplus
Initial
consumer
surplus
Quantity
(b) Consumer Surplus at Price P
Price
0
Demand
A
B
C
D E
F
P1
Q1
P2
Q2
Consumer surplus
to new consumers
Additional consumer
surplus to initial
consumers
Q2
P2
图3. 价格如何影响消费者剩余
数量
价格
0
需求
原来的消
费者剩余
原来消费者
新增的消费
者剩余
新消费者的
消费者剩余
Q1
P1
D E
F
B
C
A （b）价格在P2 时的消费者剩余
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Measuring Consumer Surplus with
the Demand Curve
用需求曲线衡量消费者剩余
The area below the demand curve
and above the price measures the
consumer surplus in the market.
需求曲线以下和价格以上的面积衡
量市场的消费者剩余。
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What Does Consumer Surplus
Measure?
Consumer surplus, the amount that
buyers are willing to pay for a good
minus the amount they actually pay
for it, measures the benefit that
buyers receive from a good as the
buyers themselves perceive it.
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消费者剩余衡量了什么？
消费者剩余， 即买者愿意为一种物
品支付的量减他们实际支付的量，
衡量了消费者从一种物品中得到的
买者自己感觉到的利益。
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Producer Surplus 生产者剩余
u Producer surplus is the amount a seller is
paid minus the seller’s cost.
生产者剩余——卖者得到的量减去卖者的
成本。
u It measures the benefit to sellers
participating in a market.
它衡量了卖者从参与市场中得到的利益。
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The Costs of Four Possible Sellers...
四个可能卖者的成本…
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Using the Supply Curve to Measure
Producer Surplus
利用供给曲线衡量生产者剩余
u Just as consumer surplus is related to
the demand curve, producer surplus is
closely related to the supply curve.
正如消费者剩余与需求曲线密切相关
一样，生产者剩余也与供给曲线紧密
相关。
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The Supply Schedule and the Supply Curve
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供给表和供给曲线
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The Supply Schedule and the Supply Curve
供给表和供给曲线
Quantity of Houses Painted
要油漆的房子数量
Price of House
Painting
油漆房子的价格
500
800
$900
0
600
1 2 3 4
Grandma’s cost格拉玛的成本
Georgia’s cost 乔治亚的成本
Frida’s cost 路易斯的成本
Mary’s cost 玛丽的成本
Supply 供给
Figure 6 How the Price Affects
Producer Surplus
Copyright©2003 Southwestern/Thomson Learning
Producer
surplus
Quantity
(a) Producer Surplus at Price P
Price
0
Supply
B
A
C
Q1
P1
图6. 价格如何影响生产者剩余
Copyright©2003 Southwestern/Thomson Learning
生产者
剩余
数量
(a) 价格在 P
价格
0
供给
B
A
C
Q1
P1
时的生产者剩余
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The area below the price and above
the supply curve measures the
producer surplus in a market.
价格以下和供给曲线以上的面积衡
量市场的生产者剩余。
Using the Supply Curve to Measure
Producer Surplus
用供给曲线衡量生产者剩余
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MARKET EFFICIENCY
and
Consumer
Surplus =
Value to
buyers
_ Amount paid
by buyers
Producer
Surplus =
Amount received
by sellers
_ Cost to
sellers
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市场效率
和
消费者剩余 = 买者的评
价
_ 买者支付的量
生产者剩余= 卖者得到的量 _ 卖者的
成本
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MARKET EFFICIENCY
or
Total
Surplus =
Value to
buyers
_ Cost to
sellers
Total
Surplus =
Consumer
Surplus
Producer
Surplus
+
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市场 效率
或
总剩余 = 买者的评
价
_ 卖者的
成本
总剩余 = 消费者剩余 生产者剩余+
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Market Efficiency 市场效率
Market efficiency is the property of a
resource allocation of maximizing
the total surplus received by all
members of society.
市场效率——资源配置使社会所有
成员得到的总剩余最大化的性质。
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Market Efficiency 市场效率
In addition to market efficiency, a
social planner might also care about
equity – the fairness of the distribution
of well-being among the various buyers
and sellers.
除了效率之外，社会计划者还应关心
平等——福利在各种买者与卖者之间
分配的公平性。
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Consumer and Producer Surplus in
the Market Equilibrium...
Price
Equilibrium
price
0 QuantityEquilibrium
quantity
A
Supply
C
B Demand
D
E
Producer
surplus
Consumer
surplus
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市场均衡时的消费者与生产者剩余...
价格
均衡价格
0 数量均衡数量
A
供给
C
B 需求
D
E
生产者剩余
消费者剩余
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Summary
u Consumer surplus equals buyers’
willingness to pay for a good minus
the amount they actually pay for it.
u Consumer surplus measures the
benefit buyers get from participating
in a market.
u Consumer surplus can be computed
by finding the area below the demand
curve and above the price.
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小结
u 消费者剩余等于买者对某种物品的支
付意愿减去买者的实际支付量。
u 消费者剩余衡量买者从参与市场中得
到的利益
u 消费者剩余可以通过找出需求曲线以
下和价格以上的面积来计算。
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Summary
u Producer surplus equals the amount
sellers receive for their goods minus their
costs of production.
u Producer surplus measures the benefit
sellers get from participating in a market.
u Producer surplus can be computed by
finding the area below the price and above
the supply curve.
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小结
u 生产者剩余等于卖者出售某种物品得到
的量减去卖者的生产成本。
u 生产者剩余衡量买者从参与市场中得到
的利益
u 生产者剩余可以通过找出价格以下和供
给曲线以上的面积来计算。
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Summary
u An allocation of resources that
maximizes the sum of consumer and
producer surplus is said to be
efficient.
u Policymakers are often concerned
with the efficiency, as well as the
equity, of economic outcomes.
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小结
u 可以说使消费者和生产者剩余的总
和最大化的资源配置是有效率的。
u 政策制定者通常关心经济结果的效
率以及平等。
