资源简介

(共26张PPT)
PUBLIC GOODS
C h a p t e r 4
Public Goods
Are goods with benefits that cannot be withheld from those who do not pay and are shared by large groups of consumers
Usually made available politically through voting on how much to supply
Are nonrival in consumption, meaning that a given quantity of a public good can be enjoyed by more than one consumer without decreasing the amounts enjoyed by rival consumers
Are nonexclusive, meaning it is too costly to exclude those who refuse to pay from enjoying the benefits
Pure Public and Pure Private Goods
Pure public good – nonrival in consumption for an entire population of consumers, nonexclusive
Results in widely consumed external benefits
Not divisible into units that can be apportioned
Pure private good – provides benefits only to the person who acquires the good, not anyone else; is rival in consumption
Results in neither positive or negative externalities
Marginal Costs of Consuming a Pure Public Good
Marginal Costs of Producing a Pure Public Good
Range of Benefits
Some public goods, such as world peace, may provide collectively consumed benefits to every individual on earth.
Some are collectively consumed within given nations, others locally consumed
Geographic range of shared benefits influences the desirability of having public goods supplied by various levels of government:
Federal, state, local
Congestible Public Goods
Goods for which crowding or congestion reduces the benefits to existing consumers when more consumers are accommodated
Marginal cost of accommodating an additional consumer is not zero after the point of congestion is reached
E.g., a user of a congested road decreases the benefits to existing users by slowing traffic, increasing accident risk
Congestible Public Goods
Price-excludable Public Goods
Goods with benefits that can be priced
Membership rights to private clubs
Schools, hospitals
Can be individually consumed and are subject to exclusion, but their production and consumption is likely to generate externalities
Alternative Means
Semipublic Goods
Exist in a continuum ranging from pure private goods to pure public goods
Goods are categorized according to the degree of rivalry in consumption and the degree of excludability
Semipublic Goods
Education as a Public Good
Has characteristics of a public good in that it creates positive externalities
Price to families set at zero; funding by government tax revenues
The idea that some citizens would purchase less than the efficient amount of education for their children if it were provided in a competitive market is behind the principle of free and compulsory public education
However, has characteristics of a public good in that government cannot guarantee that all children receive an equal amount of education
Demand for a Pure Private Good
Demand for a Pure Public Good
All consumers must consume the same quantity of the good, as pure public goods cannot be divided into individual units
Therefore, on the demand curve, the variables on the vertical axes are the maximum amounts that people would pay per unit of the pure public good as a function of the amount of the good actually available
Demand for a Pure Public Good
Efficiency of a Pure Public Good
The marginal social benefit of any given amount of a pure public good is the sum of the individual marginal benefits received by all consumers
Efficient quantity per time period corresponds to the point at which output is increased; sum of marginal benefits to consumers equals marginal social cost of the good
Efficiency conditions are:
MSB = ∑MB = MSC
Efficiency of a Pure Public Good
Efficiency of a Pure Public Good
Voluntary Contributions and Cost Sharing
By sharing costs, members of a community can pool their resources to enjoy public goods that they could not afford if they had to purchase them on their own in a market.
In small communities, pure public goods could be made available in efficient amounts, financed by voluntary contributions.
In larger communities, financing by voluntary contributions may not be feasible, because the sum of the marginal benefits of the good would likely fall short of the marginal cost.
The Lindahl Equilibrium
Named for Swedish economist Erik Lindahl
States that the voluntary contribution per unit of the public good of each member of the community equals his or her marginal benefit of the public good at the efficient level of output
Equilibrium contributions per unit of the public good sometimes called Lindahl prices
Lindahl equilibrium could be achieved by assigning each participant a Lindahl price per unit of the public good
The Lindahl Equilibrium
Equilibrium under voluntary cooperation meets the following conditions:
Amount contributed per unit of public good by each person must be adjusted so that each individual desires the identical amount of the public good
Sum of amounts contributed by each member of the community per unit must equal the marginal social cost of producing the public good
All individuals must agree voluntarily, with no coercion, on the cost-sharing arrangement and the quantity of the good
Defense Expenditure as a Share of GDP, 1962-2005
The Free-Rider Problem
A free rider is a person who seeks to enjoy the benefits of a public good without contributing anything to the cost of financing the amount made available.
This strategy almost guarantees that the equilibrium amount of a pure public good will be less than the efficient amount.
Problems become more acute in large groups, where a free rider reasons that their contribution is less likely to be needed or missed.
Voluntary Contribution
Voluntary Contribution to Finance the Marginal Social Cost of Operation Desert Shield and Desert Storm (Billions of Dollars)
Compulsory Finance
The free-rider problem is partially remedied by compulsory finance
Taxation
Payment for schooling, roads, postal services
One may decide how to vote by comparing tax share per unit of a public good with the marginal benefit at the proposed output

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