曼昆经济学原理第七版第10章 外部性 PPT课件

• Negative externalities
– Cost to society (of producing a good)
• Larger than the cost to the good producers
“All I can say is that if being a leading manufacturer means being a leading polluter, so be it.”
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• Positive externality
– Impact on the bystander is beneficial
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Figure 1
The Market for Aluminum
Externalities and Market Inefficiency
• Negative externalities
– Social cost
• Private costs of the producers (supply) • Plus the costs to those bystanders affected
Price of Aluminum
Supply (private cost)
Equilibrium
Demand
(private value)
0
QMARKET
Quantity of
Aluminum
The demand curve reflects the value to buyers, and the supply curve reflects the costs
• Efficient • Maximizes the sum of producer and
consumer surplus
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© 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Externalities
• Negative externalities
Externalities and Market Inefficiency
• Negative externalities
– Optimum quantity produced
• Maximize total welfare • Smaller than market equilibrium quantity
Externalities
• Externality
– The uncompensated impact of one person’s actions on the well-being of a bystander
– Market failure
• Negative externality
– Impact on the bystander is adverse
adversely by the negative externality
– Social cost curve is above the supply curve
• Takes into account the external costs imposed on socห้องสมุดไป่ตู้ety
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Price of Aluminum
External Cost
Optimum
Social cost (private cost and external cost)
Supply (private cost)
Equilibrium
Demand (private value)
0
QOPTIMUM QMARKET
– Why markets sometimes fail to allocate resources efficiently
– How government policies can potentially improve the market’s allocation
– What kinds of policies are likely to work best
– Exhaust from automobiles – Barking dogs
• Positive externalities
– Restored historic buildings – Research into new technologies
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Quantity of Aluminum
In the presence of a negative externality, such as pollution, the social cost of the
good exceeds the private cost. The optimal quantity, QOPTIMUM, is therefore smaller than the equilibrium quantity, QMARKET.
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Externalities
PowerPoint Slides prepared by: Andreea CHIRITESCU Eastern Illinois University
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of sellers. The equilibrium quantity, QMARKET, maximizes the total value to buyers minus the total costs of sellers. In the absence of externalities, therefore, the market
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Externalities
• Government action can sometimes improve upon market outcomes
equilibrium is efficient.
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• Government – correct market failure
– Internalizing the externality
• Altering incentives so that people take account of the external effects of their actions