This document discusses externalities and market failures related to public goods and common resources. It explains that public goods are non-excludable and non-rival, which leads to underprovision by the private market due to free-riders. Common resources are rival but non-excludable, risking overuse without regulation. Externalities occur when private actions impact others without compensation. This can cause over or underproduction. The document analyzes policy options like taxes, subsidies and regulation to correct externalities and achieve efficient outcomes.

10. Introduction
There are many goods we without paying (no Prices):
parks, national defense, clean air & water.
When goods have no prices, the market forces that
normally allocate resources are absent.
The private market may fail to provide the socially
efficient quantity of such goods

11. Important Characteristics of
Goods
Excludability: A person can be prevented from using it
 Excludable: fish tacos, wireless internet access
 Not excludable: FM radio signals, national defense
Rivalry in consumption: One person’s use diminishes
other people’s use
Rival: fish tacos
Not rival: An MP3 file of Qur’an Audio

12. The Different Kinds of Goods
Private goods: excludable, rival in consumption
Example: food
Public goods: not excludable, not rival
Example: national defense
Common resources: rival but not excludable
Example: fish in the ocean
Club goods (Natural Monopolies); Excludable & Not
rival in consumption
Example: YouTube Contents

13. Activity
Categorize the following goods in to public, common,
private or club goods
Pizza
Natural Forests
Street Lights
Magic Trick

14. Rival?
Yes
Yes
• Ice-cream cones
• Clothing
• Fire protection
• Cable TV
No
Private Goods Natural Monopolies
No
Excludable?
• Fish in the ocean
• The environment
• Tornado siren
• National defense
Common Resources Public Goods
Good Matrix

15. This chapter focuses on public goods and 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.
Public policy can potentially raise economic
well-being.

16. Public Goods
Public goods are difficult for private markets to
provide because of the free-rider problem
Free rider: a person who receives the benefit of a
good but avoids paying for it
If good is not excludable, people have incentive to
be free riders, because firms cannot prevent non-
payers from consuming the good.

17. Result:
The free-rider problem prevents private
markets from supplying public goods.
Market failure

18. The Free-Rider Problem
Solving the Free-Rider Problem
The government can decide to provide the
public good if the total benefits exceed the
costs.
The government can make everyone better off
by providing the public good and paying for it
with tax revenue.

19. Some Important Public Goods
National Defense
Basic Research
Fighting Poverty

20. The Difficult Job of Cost-
Benefit Analysis
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 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

21. A cost-benefit analysis would be used to
estimate the total costs and benefits of the
project to society as a whole.
It is difficult to do because of the absence of
prices needed to estimate social benefits and
resource costs.

22. Common Resources
Like public goods, common resources are not excludable.
 Cannot prevent free riders from using, little incentive for
firms to provide
 Role for govt: Promote to be provided
common resources: rival in consumption
 Each person’s use reduces others’ ability to use
 Role for govt: ensuring they are not overused

23. Some Important Common
Resources
 Clean air and water
 Forests, Timber
 Fish, whales, and
 other wildlife

24. Example
Case;
Overgrazing

25. Externalities and Market
Inefficiency
An Externality arises...
. . . when a person engages in an activity that influences
the well-being of a bystander
and yet neither pays nor receives any compensation for
that effect.
An externality refers to the uncompensated impact of
one person’s actions on the well- being of a bystander
Externalities cause markets to be inefficient

26. Types of Externality
When the impact on the bystander is adverse, the
externality is called a negative externality.
When the impact on the bystander is beneficial, the
externality is called a positive externality.

27. EXTERNALITIES AND MARKET
INEFFICIENCY
• Negative Externalities
• Automobile exhaust
• Cigarette smoking
• Barking dogs (loud pets)
• Loud stereos in an apartment building
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28. EXTERNALITIES AND MARKET
INEFFICIENCY
• Positive Externalities
• Immunizations
• Restored historic buildings
• Research into new technologies
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29. Externalities cause markets to be inefficient, and thus
fail to maximize total surplus.

30. Private & Social Cost
Private cost: the cost producing the good paid by the
firm
Social cost: the cost to everyone in society, including
people who do not produce or consume.
Social cost = private cost + external cost

31. Private & Social Benefit
Private benefit: benefit to the person who buys and
consumes the good
Social benefit: the total benefit to all of society
An externality occurs when private costs > or < social
cost
Or when Private Benefit is > or < social benefit

32. Externalities And Market
Inefficiency
Negative externalities lead markets to produce a larger
quantity than is socially desirable.
Positive externalities lead markets to produce a smaller
quantity than is socially desirable.

33. Welfare Economics: A Recap
• The Market for Aluminum
• The quantity produced and consumed in the market
equilibrium is efficient in the sense that it
maximizes the sum of producer and consumer
surplus.
• If the aluminum factories emit pollution (a negative
externality), then the cost to society of producing
aluminum is larger than the cost to aluminum
producers.

34. Welfare Economics: A Recap
• The Market for Aluminum
• For each unit of aluminum produced, the social cost
includes the private costs of the producers plus the
cost to those bystanders adversely affected by the
pollution.

35. Figure ; Pollution and the Social Optimum
Equilibrium
Quantity of
Aluminum
0
Price of
Aluminum
Demand
(private value)
Supply
(private cost)
Social
cost
QOPTIMUM
Optimum
Cost of
pollution
QMARKET

36. Negative Externalities
• The intersection of the demand curve and the
social-cost curve determines the optimal output
level.
• The socially optimal output level is less than the
market equilibrium quantity.

37. Negative Externalities
• Internalizing an externality involves altering
incentives so that people take account of the
external effects of their actions.

38. Negative Externalities
• Achieving the Socially Optimal Output
• The government can internalize an externality
by imposing a tax on the producer to reduce the
equilibrium quantity to the socially desirable
quantity.

39. Positive Externalities
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• When an externality benefits the bystanders, a
positive externality exists.
• The social value of the good exceeds the private
value.

40. Positive Externalities
• A technology spillover is a type of positive
externality that exists when a firm’s innovation
or design not only benefits the firm, but enters
society’s pool of technological knowledge and
benefits society as a whole.
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41. Figure ; Education and the Social Optimum
Quantity of
Education
0
Price of
Education
Demand
(private value)
Social
value
Supply
(private cost)
QMARKET QOPTIMUM
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42. Positive Externalities
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• The intersection of the supply curve and the
social-value curve determines the optimal
output level.
• The optimal output level is more than the
equilibrium quantity.
• The market produces a smaller quantity than is
socially desirable.
• The social value of the good exceeds the private
value of the good.

43. Positive Externalities
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• Internalizing Externalities: Subsidies
• Used as the primary method for attempting to
internalize positive externalities.
• Industrial Policy
• Government intervention in the economy that aims
to promote technology-enhancing industries
• Patent laws are a form of technology policy that give the
individual (or firm) with patent protection a property
right over its invention.

44. PUBLIC POLICY TOWARD
EXTERNALITIES
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• When externalities are significant and private
solutions are not found, government may
attempt to solve the problem through . . .
• command-and-control policies.
• market-based policies.

45. PUBLIC POLICY TOWARD
EXTERNALITIES
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• Command-and-Control Policies
• Usually take the form of regulations:
• Forbid certain behaviors.
• Require certain behaviors.
• Examples:
• Requirements that all students be immunized.
• Stipulations on pollution emission levels set by the
Environmental Protection Agency (EPA).

46. PUBLIC POLICY TOWARD
EXTERNALITIES
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• Market-Based Policies
• Government uses taxes and subsidies to align
private incentives with social efficiency.
• Pigovian taxes are taxes enacted to correct
the effects of a negative externality.

47. PUBLIC POLICY TOWARD
EXTERNALITIES
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• Examples of Regulation versus Pigovian Tax
• If the EPA decides it wants to reduce the amount of
pollution coming from a specific plant. The EPA
could…
• tell the firm to reduce its pollution by a specific
amount (i.e. regulation).
• levy a tax of a given amount for each unit of
pollution the firm emits (i.e. Pigovian tax).

48. PUBLIC POLICY TOWARD
EXTERNALITIES
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• Market-Based Policies
• Tradable pollution permits allow the voluntary
transfer of the right to pollute from one firm to
another.
• A market for these permits will eventually develop.
• A firm that can reduce pollution at a low cost may
prefer to sell its permit to a firm that can reduce
pollution only at a high cost.