© 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole
or in part, except for use as permitted in a license distributed with a certain product or service
or otherwise on a password-protected website for classroom use.
Microeconomics 1
Dali Laxton
Public Goods and Common Resources
Chapter 11
Masaryk University
Lecture
8

In this chapter,
look for the answers to these questions
•What are public goods?
What are common resources?
Give examples of each.
•Why do markets generally fail to provide the efficient amounts of these goods?
•How might the government improve market outcomes in the case of public goods or common resources?
Screen Shot 2013-09-29 at 9.52.07 AM.png

Introduction
§We consume many goods without paying:
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.
§One of the Ten Principles from Chapter 1:
     Governments can sometimes
     improve market outcomes.

Important Characteristics of Goods
§A good is excludable if a person can be prevented from using it.
§Excludable:  fish tacos, wireless Internet access
§Not excludable:  AM/FM radio signals, national defense
§A good is rival in consumption if one person’s
use of it diminishes others’ use.
§Rival:  fish tacos
§Not rival:
An MP3 file of RHCP’s latest single

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:  excludable but not rival
§Example:  cable TV

ACTIVE LEARNING   1
Categorizing roads
§A road is which of the four kinds of goods?
sidebar-yellow copy.png

ACTIVE LEARNING   1
Answers
§Rival in consumption?  Only if congested.
§Excludable?  Only if a toll road.
§Four possibilities:
§ Uncongested non-toll road:  public good
§ Uncongested toll road:  club good
§ Congested non-toll road:  common resource
§ Congested toll road:  private good
sidebar-yellow copy.png

The Different Kinds of Goods
§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.

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.
§Result:  The good is not produced, even if buyers collectively value the good higher than the cost
of providing it.

Public Goods
§If the benefit of a public good exceeds the cost of providing it, govt should provide the good and
pay for it with a tax on people who benefit.
§Problem:  Measuring the benefit is usually difficult.
§Cost-benefit analysis:  a study that compares
the costs and benefits of providing a public good
§Cost-benefit analyses are imprecise, so the efficient provision of public goods is more difficult
than that of private goods.

Some Important Public Goods
§National defense
§Knowledge created through basic research
§Fighting poverty

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:  seeing that they are provided
§Additional problem with common resources:
rival in consumption.
§Each person’s use reduces others’ ability
to use
§Role for govt:  ensuring they are not overused

The Tragedy of the Commons
§A parable that illustrates why common resources get used more than is socially desirable.
§Setting:  a medieval town where sheep graze on common land.
§As the population grows, the # of sheep grows.
§The amount of land is fixed,
the grass begins to disappear from overgrazing.
§The private incentives (using the land for free) outweigh the social incentives (using it
carefully).
§Result:  People can no longer raise sheep.

The Tragedy of the Commons
§The tragedy is due to an externality:
Allowing one’s flock to graze on the common land reduces its quality for other families.
§People neglect this external cost, resulting in overuse of the land.

ACTIVE LEARNING   2
Policy options for common resources
§What could the townspeople
(or their government)
have done to prevent the tragedy?
§Try to think of two or three options.
sidebar-yellow copy.png

ACTIVE LEARNING   2
Answers
§Impose a corrective tax on the use of the land
to “internalize the externality.” §Regulate use of the land (the “command-and-control” approach).
§Auction off permits allowing use of the land.
§Divide the land, sell lots to individual families; each family will have incentive not to
overgraze its own land.
sidebar-yellow copy.png

Policy Options to Prevent
Overconsumption of Common Resources
§Regulate use of the resource.
§Impose a corrective tax to internalize the externality.
§Example:  hunting & fishing licenses,
entrance fees for congested national parks
§Auction off permits allowing use of the resource.
§Example:  spectrum auctions by the
U.S. Federal Communications Commission
§If the resource is land, convert to a private good
by dividing and selling parcels to individuals.

Some Important Common Resources
§Clean air and water
§Congested roads
§Fish, whales, and other wildlife

CASE STUDY:
     “You’ve Got Spam!”
§Some firms use spam e-mails
to advertise their products.
§Spam is not excludable:
Firms cannot be prevented
from spamming.
§Spam is rival:  As more
companies use spam, it becomes less effective.
§Thus, spam is a common resource.
§Like most common resources, spam is overused – which is why we get so much of it!
“Spam” email is named after everyone’s
favorite delicacy.
©Paul Maguire/Shutterstock.com
A can of food Description automatically generated

CONCLUSION
§Public goods tend to be under-provided, while common resources tend to be over-consumed.
§These problems arise because property rights
are not well-established:
§Nobody owns the air, so no one can charge polluters.  Result:  too much pollution.
§Nobody can charge people who benefit from national defense.  Result:  too little defense.
§The govt can potentially solve these problems
with appropriate policies.

Summary
•A good is excludable if someone can be prevented from using it.  A good is rival in consumption if
one person’s use reduces others’ ability to use the same unit of the good.  •Markets work best for
private goods,
which are excludable and rival in consumption.  Markets do not work well for other types of goods.
Screen Shot 2013-09-29 at 9.52.07 AM.png

Summary
•Public goods, such as national defense and fundamental knowledge, are neither excludable nor rival
in consumption.  •Because people do not have to pay to use them, they have an incentive to free
ride, and firms have no incentive to provide them.  •Therefore, the government provides public
goods, using cost-benefit analysis to determine how much to provide.
Screen Shot 2013-09-29 at 9.52.07 AM.png

Summary
•Common resources are rival in consumption but not excludable.  Examples include common grazing
land, clean air, and congested roads. •People can use common resources without paying, so they tend
to overuse them.
Therefore, governments try to limit the use of common resources.
Screen Shot 2013-09-29 at 9.52.07 AM.png