曼昆微观经济学ch11

Free rider: a person who receives the benefit of
a good but avoids paying for it
PUBLIC GOODS AND COMMON RESOURCES
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Public Goods
The government can make everyone better
Introduction
The best things in life are free and we consume
many goods without paying: parks, national defense, clean air, etc.
When goods have no prices, the market forces
Rivalry
Rivalry refers to the property of a good
whereby one person’s use diminishes other people’s use.
PUBLIC GOODS AND COMMON RESOURCES
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The Different Kinds of Goods
off by providing the public goods and paying for them with tax revenue.
Government should provide the public
good if the benefit exceeds the cost.
PUBLIC GOODS AND COMMON RESOURCES
When thinking about the various goods in
the economy, it is useful to group them according to two characteristics: Is the good excludable? Is the good rival?
PUBLIC GOODS AND COMMON RESOURCES
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Introduction
When a good does not have a price attached to it,
private markets cannot ensure that the good is produced and consumed in the proper amounts.
provide because of the free-rider problem.
Since people cannot be excluded from enjoying
the benefits of a public good, individuals may withhold paying for the good hoping that others will pay for it.
PUBLIC GOODS AND COMMON RESOURCES
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Four Types of Goods
Yes
Rival
No
Yes
Excludable
Private Goods •Ice-cream cones •Clothing •Congested toll roads
Natural Monopolies •Fire protection •Cable TV •Uncongested toll roads
Common Resources
Common resources tend to be used excessively
when individuals are not charged for their usage.
This is similar to a negative externality.
No
Common Resources •Fish in the ocean •The environment •Congested nontoll roads
Public Goods •Tornado siren •National defense •Uncongested nontoll roads
common resources.
For both, externalities arise because something
of value has no price attached to it.
So, private decisions about consumption and
production can lead to an inefficient outcome.
percent, and the cost is $10,000.

The value of a human life is about $10 million.
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Common Resources
Like public goods, common resources are not
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Snow plowing Education Rural roads City streets
PUBLIC GOODS AND COMMON RESOURCES
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The Different Kinds of Goods
This chapter focuses on public goods and
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Categorizing roads
Rival in consumption? Only if congested. Excludable? Only if a toll road.
Four possibilities:
Uncongested non-toll road: public good Uncongested toll road: natural monopoly Congested non-toll road: common resource Congested toll road: private good
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PUBLIC GOODS AND COMMON RESOURCES
Categorizing roads
A road is which of the four kinds of goods? Hint: The answer depends on whether the road
is congested or not, and whether it’s a toll road or not. Consider the different cases.
CHAPTER
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Public Goods and Common Resources
Economics
PRINCIPLES OF
N. Gregory Mankiw
bannannan@dufe.edu.cn
© 2009 South-Western, a part of Cengage Learning, all rights reserved
Public policy can potentially raise economic
well-being.
PUBLIC GOODS AND COMMON RESOURCES
百度文库
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Public Goods
Public goods are difficult for private markets to
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Some Important Public Goods
National defense Basic research General knowledge vs. specific technological
knowledge
Fighting poverty
PUBLIC GOODS AND COMMON RESOURCES
that normally allocate resources are absent.
Most goods in our economy are allocated by
price signals that guide the decisions of buyers and sellers.
Free goods provide a special challenge.
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Case Study: How Much Is A Life Worth?
The decision to place a stoplight at a busy
intersection to reduce the risk of fatal accidents.
The traffic light reduces the risk of fatality by 0.5
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The tragedy of the commons is a parable that
illustrates why common resources get used more than is socially desirable.
or not, the total benefits of all those who use the good must be compared to the costs of providing and maintaining the public good.
PUBLIC GOODS AND COMMON RESOURCES
PUBLIC GOODS AND COMMON RESOURCES
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The Different Kinds of Goods
Excludability
Excludability refers to the property of a good
whereby a person can be prevented from using it.
excludable. They are available free of charge to anyone who wisher to use them.
Common resources are rival goods because one
person’s use of the common resource reduces other people’s use.
In such cases, government policy can potentially
remedy the market failure and raise economic well-being.
PUBLIC GOODS AND COMMON RESOURCES
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The Different Kinds of Goods
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Case Study: Are Lighthouses Public Goods?
PUBLIC GOODS AND COMMON RESOURCES
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Public Goods
The government must then determine what kinds
of public goods to provide and in what quantities.

Private Goods: excludable, rival Public Goods: not excludable, not rival Common Resources: not excludable, rival Natural Monopolies: excludable, not rival
Cost-benefit analysis refers to a study that
compares the costs and benefits to society of providing a public good.
In order to decide whether to provide a public good