1. Topic 5：Public Goods

2. The Different Kinds Of Goods
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?

3. Excludability Rivalry
Excludability refers to the property of a good whereby a person can be prevented from using it.
Rivalry
Rivalry refers to the property of a good whereby one person’s use diminishes[di’miniʃ] other people’s use.

4. Four Types of Goods Private Goods Public Goods Common Resources
Natural Monopolies

5. Private Goods Public Goods Common Resources Natural Monopolies
Are both excludable and rival.
Public Goods
Are neither excludable nor rival.
Common Resources
Are rival but not excludable.
Natural Monopolies
Are excludable but not rival.

6. Four Types of Goods [tɔ:‘neidəu]龙卷风 [‘saiərin]警报 Rival? Yes No
Private Goods
Natural Monopolies •
Ice-cream cones
Clothing
Congested toll roads •
Fire protection
Cable TV
Uncongested toll roads
Yes
Excludable?
Common Resources
Public Goods •
Fish in the ocean
The environment
Congested nontoll roads •
Tornado siren
National defense
Uncongested nontoll roads No
[tɔ:‘neidəu]龙卷风
[‘saiərin]警报
Copyright © South-Western

7. Characteristics of Public Goods
Characteristics of Public Goods(figure 5.3)
irrigation灌溉
Non-rivalry

8. The Mathematic Definition of Rublic Goods
The formula of the public goods:
In this formula, every consumer(j ) can consume the public goods with total amounts according to his wish, that is, public goods between individuals can not be divided.

9. (1)Collective Consumption Goods
A collective consumption good is a good for which the consumption by one consumer will not reduce the consumption of any other consumer.(non-rivalry)
a good example is a radio broadcast signal.
ecnomists sometimes call a collective consumption good a public good.
it does not have to be produced in the public sector of the economy

10. The Argument for Public Sector Production
Assume that the cable company charges $10 per month for a subscriber to receive a movie channel.
If the subscriber is willing to pay only $5, he will not get the channel.
The possible social value is reduced by $5.

11. It would be possible to set a price so that both the cable company and the viewer would be better off, making a Pareto superior move.
Because the marginal cost of adding an additional viewer is zero, the social value will be maximized when everyone who places any value at all is allowed to consume it.

12. This is argument for financing the goods through tax and distributing it at no cost to anyone who wants it.

13. The Argument for Private Sector Production
When the movie theater fills up, it takes on more of the characteristics of a private consumption good.
Seen in this light, many things that appear to be collective consumption goods(uncongested highways serve as a perfect example) may actually be private consumption goods that have been overproduced.

14. Cost (Dollars)
Number of Consumers
200
Marginal Cost of Allowing an
Additional Person to Consume a
Given Quantity of Pure Public Good 1

15. Number of Consumers per Hour
Marginal Cost 1
Marginal Cost per User

16. Yet some goods seem not to be susceptible [sə’septəbl易受影响的] to congestion at all.
Information might provide a good example.
television broadcast signal

17. Even in the case in which there is no congestion problem, there still may be a good reason to produce the good in the private sector.
can provide a market signal for efficiently allacating resources
Fg. Consumers can choose from several cable channels that show music, weather, sports, and so on. If these services were all given away free, producers would have no idea about the value of each service.

18. The Optimal Output of a Colletive Consumption Goods
Given the special characteristics of a collective consumption goods, how much of the goods should be produced?

19. For a private good, the optimal level of production occurs at the point where the marginal benefits of additional production equal the marginal cost.

20. Can the general principle holds for collective consumption goods?
For private goods, the market demand is found by horizontally(水平地） summing all the individual demand curves to get the market demand curve.

21. Efficient Provision of Private Goods
Price
Adam (DfA)
Eve (DfE)
Market (DfA+E)
$11 5 1 6 $9 7 3 10 $7 9 14 $5 11 18 $3 13 22 $1 15 26

22. $ Sf
DfA+E
DfA
DfE
Quantity of Pizza

23. For collective consumption goods, each unit produced can be consumed by , and is valued by, all consumers.
Vertical（垂直的） summation of individual demand curves

24. Efficient Provision of Colletive Consumption Goods
Units of Fireworks 1 2 3 4
Adam (DrA)
$300
$250
$200
$150
Eve (DrE)
$ 250
$ 200
$ 150
$ 100
Market (DrA+E)
$550
$450
$350

25. $ Sr
DrA+E
DrA
DrE
Quantity of Fireworks

26. Lindahl Pricing
Lindahl prices for public goods are set so that each individual pays a marginal price equal to the marginal benefit the individual receives from consuming the good.
Is it unfair?
Is it practical?

27. (2)Nonexcludability
A good is nonexcludable if once produced, it is difficult to keep people from consuming the good.

28. Free Riders
There is no way to provide some goods and services without benefiting everyone.
Households do not have the incentive to pay what the item is worth to them.
Free riders understate the value of a good or service so that they can enjoy its benefit without paying for it.

29. Nonexcludability as a Prisoners' Dilemma
The prisoners' dilemma [di’lemə](figure 5.2) B A
Not confess
confess
-3，-3
-15，-1
-1，-15
-10，-10

30. Individuals have the incentive to free ride, but they would be better off if they all cooperated to produce the goods.
When they act in their own narrow self-interests, they end up worse off than if they all had placed the common interest above their own interests.
In competitive markets, individuals pursuing their own self-interests are led by an invisible hand to further the best interest of the whole society Adam Smith. The Wealth of Nations, 1776

31. Nonexcludability tends to be a matter of degree, reflecting how costly it would be to keep people from consuming the goods.
Tolls on highways or on city streets?

32. Public Policy toward Public Goods
National defense and microcomputer software share the characteristices of nonexcludable and collective consumption goods.
Why is notional defense produced in the public sector and microcomputer software produced in the private sector?
???

33. Case1: Clean Air Clean Air is a public good
Nonexclusive and nonrival
What is the price of clean air?

34. Choosing where to live
Study in Boston correlates housing prices with the quality of air and other characteristics of the houses and their neighborhoods.

35. Findings
Amount people are willing to pay for clean air increases substantially as pollution increases.
Higher income earners are willing to pay more (the gap between the demand curves widen)
National Academy [ə’kædəmi] of Sciences found that a 10% reduction in auto emissions yielded a benefit of $2 billion---somewhat greater than the cost.

36. Government production of a public good is advantageous because the government can assess taxes or fees to pay for it.
Determining how much of a public good to provide when free riders exist is difficult.

37. Case 2: Government Intervention in Education
Does Government Intervention Crowd Out Private Education? A x
Quantity of all other goods
Private School quantity of education ii
Public schooling “crowds out” education i B ep e0
Quantity of Education

38. Public schooling increases quantity of education
Does Government Intervention Crowd Out Private Education? A x
Quantity of all other goods ii i
Public schooling increases quantity of education B e0 ep
Quantity of Education

39. Public schooling does not increase quantity of education
Does Government Intervention Crowd Out Private Education? A x
Quantity of all other goods
Public schooling does not increase quantity of education i B ii ep e0
Quantity of Education

40. Case 3: Lighthouse