princ-ch22-presentation6e mankiw_6版微觀經(jīng)濟學(xué)部分12-22章完整PPT(全英文).ppt

1、,N. Gregory Mankiw,22,In this chapter, look for the answers to these questions:,How does asymmetric information affect market outcomes? How can market participants reduce the resulting problems? Why might democratic voting systems fail to represent the preferences of society? Why do people not alway

2、s behave as rational maximizers?,Introduction,Microeconomics continues to evolve. This chapter introduces three active areas of research: Asymmetric information Political economy Behavioral economics,0,Asymmetric Information,Information asymmetry: a difference in two or more parties access to releva

3、nt knowledge Two types: Hidden actions one person knows more than another about an action he or she is taking. Hidden characteristics one person knows more than another about the attributes of good he or she is selling.,0,Hidden Actions and Moral Hazard,Moral hazard: the tendency of a person who is

4、imperfectly monitored to engage in dishonest or otherwise undesirable behavior Workers sometimes shirk their responsibilities because their employer cannot continually monitor their effort and performance. Someone whose property is insured may not try as hard to protect it from theft/damage. While t

5、he parents are out, the babysitter may spend more time watching videos than watching the children.,0,The Principal-Agent Problem,Agent: a person who is performing a task on someone elses behalf (e.g., a worker) Principal: the person for whom this action is being performed (e.g., an employer) When th

6、e principal cannot perfectly monitor the agents behavior, there is a risk (“hazard”) that the agent may do something undesirable (“immoral”). Example: Worker may play video games or surf the web while on the clock.,0,How Principals May Respond,Better monitoringParents plant hidden cameras in the hom

7、e to increase the chance of detecting undesirable behavior. Higher wagesEmployers pay workers efficiency wages (wages above the equilibrium level) to increase the penalty for being caught shirking. Delayed paymentFirms delay payment (e.g., year-end bonuses) to increase the penalty for being caught s

8、hirking.,0,Corporate Management,The separation of ownership and control of corporations creates a principal-agent problem: Principals: the shareholders, pay managers to maximize the firms profits Agents: the managers,may pursue their own objectives Shareholders hire a board of directors to oversee m

9、anagement, create incentives for management to pursue the firms goals instead of their own. Corporate managers sometimes sent to jail for taking advantage of shareholders.,0,Hidden Characteristics and Adverse Selection,Adverse selection arises when the seller knows more than the buyer about the good

10、 being sold. Example 1: The market for used cars The seller knows more than the buyer about the quality of the car being sold. Owners of “l(fā)emons” more likely to put their vehicles up for sale. So buyers are more likely to avoid used cars. Owners of good used cars less likely to get a fair price, so

11、may not bother trying to sell.,0,Hidden Characteristics and Adverse Selection,Example 2: Insurance Buyers of health insurance know more about their health than health insurance companies. People with hidden health problems have more incentive to buy insurance policies. So, prices of policies reflect

12、 the costs of a sicker-than-average person. These prices discourage healthy people from buying insurance. In both examples, the information asymmetry prevents some mutually beneficial trades.,0,Market Responses to Asymmetric Information,Signaling: action taken by an informed party to reveal private

13、information to an uninformed party Individual selling a good used car provides all receipts for work done on car. Dealership provides warranties on used cars. Firms spend huge sums on advertising to signal product quality to buyers. Highly competent workers get college degree to signal their quality

14、 to employers.,0,Market Responses to Asymmetric Information,Screening: action taken by an uninformed party to induce informed party to reveal private information Health insurance company requires physical exam before selling policy. Buyer of a used car requires inspection by a mechanic. Auto insuran

15、ce company charges lower premiums to drivers willing to accept a larger deductiblethey are most likely the safer drivers.,0,Asymmetric Information and Public Policy,Asymmetric information may prevent market from allocating resources efficiently. Yet, public policy may not be able to improve on the m

16、arket outcome: Private markets can sometimes deal with the problem using signaling or screening. The govt rarely has more information than private parties. The govt itself is an imperfect institution.,0,ACTIVE LEARNING 1 Asymmetric information, 2012 Cengage Learning. All Rights Reserved. May not be

17、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.,A.Aperion Audio sells home theater sound systems over the Internet and offers to refund the purc

18、hase price and shipping both ways if the buyer is not satisfied. B. Landlords require tenants to pay security deposits.,For each situation below, identify whether the problem is moral hazard or adverse selection explain how the problem has been reduced,ACTIVE LEARNING 1 Answers, part A, 2012 Cengage

19、 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.,Adverse selection: Buyers may fear that systems purch

20、ased on the Internet will not sound good, since the sellers know that buyers cannot hear them first. So, firms with good systems are less likely to be successful selling them on the Internet. Aperion Audio reduces the problem by signaling high quality with its generous return policy.,Aperion Audio s

21、ells home theater sound systems over the Internet and offers to refund the purchase price and shipping both ways if the buyer is not satisfied.,ACTIVE LEARNING 1 Answers, part B, 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for us

22、e as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.,Moral hazard: The landlord (principal) does not know how well the tenant (agent) treats the apartment. Tenants may not be careful if they can get away without pay

23、ing for damage they cause. The security deposit increases the likelihood the tenant will take care of the property in order to receive his deposit back when he moves out.,Landlords require tenants to pay security deposits.,Political Economy,Political economy applies the methods of economics to study

24、 how government works. First, we consider voting. Condorcet paradox: the failure of majority rule to produce transitive preferences for society. Transitivity is a property of preference rankings: If A is preferred to B, and if B is preferred to C, then A should be preferred to C.,0,Example of the Co

25、ndorcet Paradox,A, B, and C are three candidates running for an open seat on the city council. There are 3 types of voters, each with its own rankings of the candidates:,0,Example of the Condorcet Paradox,Suppose pair-wise voting: First, B runs against C: B wins. Then, A runs against B: A wins. The

26、overall winner: A,Alternative order: First, A runs against C: C wins. Then, C runs against B: B wins. The overall winner: B,0,Lessons from the Condorcet Paradox,Democratic preferences are not always transitive. The order on which things are voted can affect the result. Majority voting does not alway

27、s reveal what society really wants.,0,Arrows Four Desirable Properties of a Voting System,1.Unanimity: If everyone prefers A to B, then A should beat B. 2.Transitivity: If A beats B, and B beats C, then A should beat C. 3.Independence of irrelevant alternatives: The ranking between any two outcomes

28、should not depend on whether a third option is available. 4.No dictators: There is no person who always gets his way, regardless of everyone elses preferences.,0,Arrows Impossibility Theorem,Arrow proved that no voting system can satisfy all four properties. Arrows impossibility theorem: a mathemati

29、cal result showing that, under certain assumed conditions, there is no scheme for aggregating individual preferences into a valid set of social preferences,0,The Median Voter Theorem,Suppose society is deciding the level of the government budget. Each voter has her own preferences about the size of

30、the budget. If you line up all voters in order of their budget preferences, the median voter is the one right in the middle. Median voter theorem: a mathematical result showing that majority rule will always pick the outcome most preferred by the median voter,0,Preferred govt budget (billions),The m

31、edian voter prefers a budget of $50 billion.,Example of the Median Voter Theorem,The choice closest to $50 will win any two-way race. Suppose the choices are $40 and $70. $40 will win, even though more voters prefer $70!,0,Implications of the Median Voter Theorem,In a two-party or two-candidate race

32、, each party will move its position toward that of the median voter. Minority views are not given much weight.,0,Politicians are People Too,Politicians motivated by self-interest, just like firms and consumers. Some politicians motivated by re-election, willing to sacrifice the national interest tow

33、ard that goal. Others motivated by greed. The lesson: Economic policy is not made by benevolent leaders, and sometimes fails to resemble the ideals derived in economics textbooks.,0,ACTIVE LEARNING 2 Application of the Median Voter Theorem,Would you expect the Democratic presidential nominee to be m

34、ore liberal during the primaries or the general election, or to be consistent throughout both? Would you expect the Republican nominee to be more conservative during the primaries or the general election, or to be consistent throughout both?, 2012 Cengage Learning. All Rights Reserved. May not be co

35、pied, 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.,ACTIVE LEARNING 2 Answers,The median voter in Democratic primaries is more liberal than the median

36、 voter in the general election. So, the Democratic candidates best strategy is to act more liberal during the primaries and more centrist during the general election. Similarly, the Republican candidate will want to appeal more to the median Republican voter during the primaries, and then appear les

37、s conservative during the general election., 2012 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 u

38、se.,Behavioral Economics,Behavioral economics: the subfield of economics that integrates the insights of psychology People arent always as rational as traditional economic models assume. Herbert Simon viewed humans as satisficers,people who make choices that are merely “good enough” rather than opti

39、mal. Other economists have suggested that people are only “near rational” or exhibit “bounded rationality.”,0,People Arent Always Rational,Studies find that people make systematic mistakes: People are overconfident. People give too much weight to a small number of vivid observations. People are relu

40、ctant to change their minds. Even though people are not always rational, the assumption that they are is usually a good approximation for economic modeling.,0,People Care About Fairness,Peoples choices are sometimes influenced more by their sense of fairness than self-interest. Example: The ultimatu

41、m game The rules Two players who do not know each other have a chance to share a prize of $100. Player A decides what portion of the prize to give to player B. B must accept the split or both get nothing.,0,People Care About Fairness,Predicted outcome if both players rational A would propose a 99-1

42、split and B would accept, because $1 is better than nothing. Actual outcomes from experiments with real people B usually rejects lopsided splits like 99-1 as wildly unfair. Expecting this, A usually proposes giving $30 or $40 to B. B views this as unfair, but not so much as to abandon his self-inter

43、est, so B accepts.,0,People Care About Fairness,The results of the ultimatum game apply in other situations. Example: A firm may pay above-equilibrium wages during profitable years to be fair, or to avoid appearing unfair and risking retaliation from workers.,0,People Are Inconsistent Over Time,Peop

44、le tend to prefer instant gratification, even when delaying would increase the gratification. Result: People fail to follow through on plans to do things that are dreary, take effort, or cause discomfort. E.g., people often save less than they plan To help follow through, people look for ways to com

45、mit themselves to their plans. E.g., worker has money taken out of paycheck before he ever sees it,0,CONCLUSION,Recall two of the Ten Principles from Chapter 1: Markets are usually a good way to organize economic activity. Governments can sometimes improve market outcomes. Research at the frontiers

46、of microeconomics illustrates some caveats that go with these principles: Consumers arent always rational. Market outcomes may not be best when information is asymmetric. Government solutions are not always ideal.,0,SUMMARY,In many transactions, information is asymmetric. When there are hidden actions, principals may be concerned that agents suffer from the problem of moral hazard. When there are hidden characteristics, buyers may be concerned about the problem of adverse selection among the sellers. Private markets sometimes deal with asymmet