财政学的福利经济学基础

Efficiency Conditions with variable production
无花果叶 60
产品组合效率要求 MRS = MRT
生产可能性曲线
C
斜率=MRT 为了多生产一个苹果 需要放弃几片无花果叶
斜率=MRS 消费者为了多消费一个 苹果，愿意放弃几片无 花果叶
消费者无差异曲线
100
Efficiency versus Equity Eve
r
0’
Fig leaves per year
p3
p5
q
0 Adam
s
Apples per year
Edgeworth Box
效用可能性曲线: It shows the maximum amount of one person’s utility given the other individual’s utility level.
Adam af
MRSaEfve
追求利润最大化 MCa Pa MC f Pf
MRTaf
Pa Pf
MRSaAfdam
MRSaEfve
MRSaEfve
Pa Pf
竞争可以保证帕累托效率条件的实现
三、 Fairness and the second fundamental theorem of welfare economics
一、福利经济学 （ Welfare Economics） 1 Pure Economy Exchange 2 Production Economy
二、福利经济学第一基本定理 三、 公平与福利经济学第二基本定理 四、 市场失败 五、 福利经济学的局限
一、福利经济学
• 福利经济学: The branch of economic theory
• Moreover, governments , like people, can make mistakes.
五、福利经济学的局限
• Individualistic outlook: Welfare Economics is based on an individualistic social philosophy.
• 生产可能性曲线The production possibilities curve • 边际转换率The marginal rate of transformation
MRTaf wy MCa xz MCf
• 产品组合效率条件Efficiency conditions with variable production
• Pareto efficiency requires that the marginal rate of substitution be equal for all consumers
MRS MRS af ( Adam)
af ( Eve)
Edgeworth Box: A device used to depict the distribution of goods in a two good-two person world.
Homework
• Discussion questions
•
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•
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• 市场势力 Market Power
– 垄断 monopoly
• 市场不存在 Nonexistence of Markets
– 信息不对称 asymmetric information – 外部性 externality – 公共商品 public good
Overview
• The First Welfare Theorem of states that a properly working competitive economy generates a Pareto efficient allocation of resources without any government intervention. However, it is not obvious that an efficient allocation of resources is per se socially desirable; some argue that fairness must also be considered. Moreover, competition may not hold and not all markets may exist in realworld economies. Hence, the market-determined allocation of resources is unlikely to be efficient. There are, then opportunities for government to intervene and enhance economic efficiency.
• Merit goods: A commodity that ought to be provided even if people do not demand it
• Results orientation: Welfare Economics concerns only the results, it does not pay much attention to the processes used to achieve results.
第二讲 财政学的福利经济学基础 （规范分析工具）
政府的经济活动多种多样，评价种种不同的 政府行为的合理性需要有一个一般性框架。 财政学领域的大多数专家使用的评价分析框架 是福利经济学。
本讲介绍福利经济学的基本内容，用以区分 哪些情况市场运作自发带来理想结果，哪些情 况市场无法产生理想结果。
第二讲 财政学的福利经济学基础
• 帕累托改进Pareto improvement: a reallocation of resources that makes one person better off without making anyone else worse off.
• 契约曲线Contract curve: the locus of all the Pareto efficient points.
certain conditions, a Pareto efficient allocation of
resources emerges. • 只要生产者和消费者扮演完全竞争者的角色，即
接受给定的价格,竞争的经济会“自动”实现帕 累托有效的资源配置。
追求效用最大化
MRSaAfdam
Pa Pf
MRS
Maximizing Social Welfare
i iii ii Eve’s utility
福利经济学第二基本定理：
在完全竞争的市场条件下，政府所要做 的事情是改变个人之间禀赋的初始分配 状态，其余的一切都可以由市场来解决。 每一种具有帕累托效率的资源配置都可 以通过市场机制实现。
四、市场失败 Market Failure
MRTaf MRSaAfdam MRSaEfve
生产可能性曲线Production possibilities curve: A graph that shows the maximum quantity of one output that can be produced, given the amount of the other output.
If properly functioning competitive markets allocate resources efficiently, what role does the government have to play in the economy? 效率不是决定某种资源配置好坏的惟一标准。 即使经济实现了帕累托效率，为了效用分 配更加公平，政府仍有必要干预经济。
苹果
边际转换率Marginal Rate of Transformation
• MRTaf = Marginal rate of transformation of apples for fig leaves
• MRTaf = MCa/MCf
帕累托效率条件
Adam
Eve
MRTaf = MRSaf = MRSaf
Making both Adam and Eve better off
Fig leaves per year
Starting from a different initial point Eve
r
0’
Eg g
k
Ep2
p4
p
Apples per year
Edgeworth Box
无差异曲线 Indifference curves in an Edgeworth Box
Making Adam better off without Eve becoming worse off
Making Eve better off without Adam becoming worse off
• Coherent framework for analyzing policy
– Will it have desirable distributional consequences?
– Will it enhance efficiency? – Can it be done at a reasonable cost?
Adam
Eve
MCa/MCf = MRSaf = MRSaf
二、福利经济学第一基本定理
The First Fundamental Theorem of Welfare Economics
As long as producers and consumers act as perfect
competitors, that is, take prices as given, then under
Overview
• The fact that the market-generated allocation of resources is imperfect does not necessarily mean the government is capable of doing better.
Edgeworth Box
Ap2
Ag s
Pareto Efficiency in Consumption 消费效率条件
Adam
MRSaf
Eve
= MRSaf
• 在纯交换经济下，帕累托效率的实 现条件为社会所有成员的边际替代 率相等
2 生产经济Production Economy （有生产，有交换）
concerned with the social desirability of alternative economic state.
1.简单经济交换 （没有生产）
• 埃奇沃斯盒形图Edgeworth Box
• 帕累托效率Pareto efficient allocation: No person can be better off without making another person worse off.
Ap2
Ag s
Fig leaves per year
Contract curve: The locus of all the
Pareto efficient points.(契约曲线) Eve
r
0’
Eg g Ep2
p p2 p1
p4 p3
The contract curve
0 Adam
Apples per year
Adam’s utility
U p3
q
p5
U Eve’s utility
Adam’s utility
社会无差异曲线 Social Indifference Curve
W = F(UAdam, UEve)
Increasing social welfare
Eve’s utility
Adam’s utility