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1、微微观经济学学讲解解12-2LO 12- AllLearning Objectives1.Explain how middlemen add value to market transactions2.Use the concept of rational search to find the optimal amount of information market participants should obtain3.Define asymmetric information and describe how it leads to the lemons problem4.Discuss
2、how advertising, conspicuous consumption, statistical discrimination, and other devices are responses to asymmetric information12-3LO 12- AllInformation and the Invisible HandAll parties have all relevant informationWithout free information, market results are not efficientBargaining for a bowl in K
3、ashmirParties must decide how much information to gatherInformation gathering strategies differ12-4LO 12 - 1The Middleman Adds ValueBuyers sometimes choose among several version of a productEach has complex feature setsResearch optionsCompany web siteAsk friends and familyConsumer Reports, online pr
4、oduct reviewsVisit stores, ecommerce sites12-5LO 12 - 1Buying SkisSkis R Us recommend $600 Salomon X-Scream 9 skisSales rep seems knowledgeableYour next move isThank them and do more researchTrust the sales rep and buy themGo home and buy at the best price online ($400)Evaluate the importance ofImme
5、diate possessionBest pricePost-sales service and support12-6LO 12 - 1The Value of the MiddlemanSales representatives supply information to buyersManufacturers can offer direct sales to bypass middlemenInformation makes markets more efficientPurchasing the bowl in Kashmir12-7LO 12 - 1Selling Babe Rut
6、hEllis wants to sell a Babe Ruth baseball card.His reservation price is $300An ad in the local newspaper cost $5eBay cost is 5% of the Internet auction priceThe maximum price in the local market is $400Two eBay shoppers have secret reservation prices of $800 and $900, respectively12-8LO 12 - 1Sellin
7、g Babe RuthBenefits of eBayCard sells for $800 on eBay less $40 commissionEllis nets $760, $460 above his reservation priceBuyer surplus is $100Local option is inferiorCard sells for $400 less $5 cost of adEllis nets $395, $95 more than his reservation priceBuyer surplus is $0Economic surplus is inc
8、reased when a product goes to the person who values it the most12-9LO 12 - 2$/unitUnits of informationMBThe Optimal Amount of InformationMore information is better than lessGathering information has a costMarginal benefit starts high, then falls rapidlyLow-Hanging Fruit PrincipleMarginal cost starts
9、 low, then increasesOptimal amount of information is I* where MC = MBMCI *Optimal12-10LO 12 - 2Free Rider ProblemA free-rider problem exists when non-payers cannot be excluded from consuming a goodInterferes with incentivesMarket quantity is below social optimumStores bear the cost of training sales
10、 reps on merchandiseShoppers use sales reps as information sourceThen some shoppers buy elsewhereStore is unable to capture some of the value it delivered to the shopper: a free-rider problem12-11LO 12 - 2The Last BookstoreIndependent bookstores differentiate themselves with personalized serviceOffe
11、r more information and recommendations than Barnes & Nobles or BordersChain bookstores carry large inventory and shopping center location can erode local store baseEcommerce sites such as Amazon and Overstock offer reviews and recommendationsLarge inventory; quick deliveryOnline sales further reduce
12、 sales in independent stores12-12LO 12 - 2Rational Search GuidelinesAdditional search time is more likely to be worthwhile for expensive items than cheap onesApartment search in Paris, Texas involves less time than Paris, FranceTexas has lower rents and narrower price rangePrices paid will be higher
13、 when the cost of a search is higherTwo buyers, only one with a carBuyer with the car will look at more pianos before buying12-13LO 12 - 2Gamble Inherent in SearchAdditional search has costs that are certainBenefits are uncertain benefitsAdditional search has elements of a gambleA gamble has a numbe
14、r of possible outcomesEach outcome has a probability that it will occur12-14LO 12 - 2Gamble Inherent in SearchThe expected value of a gamble is the sum of (the possible outcomes times their respective probability)A fair gamble has an expected value of zeroA better-than-fair gamble has a positive exp
15、ected value12-15LO 12 - 2Risk PreferencesA risk-neutral person would accept any gamble that is fair or better-than-fairA risk-averse person would refuse any fair gamble12-16LO 12 - 2San Francisco Apartment SearchYou need a one-month sublet in San FranciscoOne type of apartment rents for $400 and it
16、is 80% of the available market The other type rents for $360 and makes up 20% of the marketYou must visit the apartment to get the rental rateCost per visit is $6You are risk-neutral12-17LO 12 - 2San Francisco Apartment SearchThe first apartment you visit is the $400 versionLook at the next apartmen
17、t if the gamble is at least fairTwo outcomes to the gambleYou find a lower-priced apartment and your net benefit is $34 with 20% probabilityYou find another $400 apartment and your net benefit is $6 with 80% probabilityExpected value of the gamble is (34) (0.20) + ( 6) (0.80) = $2 Keep searching12-1
18、8LO 12 - 2Commitment Problems and SearchSome searches are for circumstances requiring commitment over some period of timeLeasing an apartmentTaking a jobGetting marriedSearch is costly and therefore limitedPeople end their searches when the marginal cost of searching exceeds the marginal benefitBUT
19、what if you fall into a better option?12-19LO 12 - 2Commitment Problems and SearchIf information were freely available, there would be no commitment problemContracts are used to bind parties together ANDContracts carry penalties for breaking the arrangementPeople terminate their search because infor
20、mation gathering is costlyUnder some circumstances, one party may rationally choose to terminate the agreement and pay the penalties12-20LO 12 - 3Asymmetric InformationAsymmetric information occurs when either the buyer or seller Is better informed about the goods in the marketMutually beneficial tr
21、ades may not occurA seller might know thata murder was committed in a house offered for saleBuyer does not know12-21LO 12 - 3Private Sale of a Used CarJanes Miata is in excellent conditionJanes reservation price is $10,000Blue Book value is $8,000Tom wants to buy a MiataHis reservation price is $13,
22、000 for one in excellent condition and $9,000 for one in average conditionDetermining the condition of Janes car has a cost and the results are uncertainTom cannot verify that Janes Miata is superiorTom buys another Miata for $8,000; Janes is unsold12-22LO 12 - 3Surplus Loss and Asymmetric Informati
23、onToms loss is $1,000Pays $8,000 and has a gain of $1,000 Toms loss from buying an average car instead of Janes$13,000 $11,000 = $2,000Toms net loss is $1,000Janes loss from losing Tom as a customer is $1,000Total loss is $2,00012-23LO 12 - 3The Lemons ModelPeople who have below average cars (lemons
24、), are more likely to want to sell themBuyers know that below average cars are likely to be on the market and lower their reservation pricesGood quality cars are withdrawn from the marketAverage quality decreases further and reservation prices decrease againThe lemons model says that asymmetric info
25、rmation tends to reduce the average quality of goods for sale12-24LO 12 - 3Your Aunts CarYour aunt offers you her 4-year old AccordThe asking price of $10,000 is the blue book valueYou believe the car is in good conditionBlue book value is the equilibrium price for below average carsYou should buy t
26、he car for $10,000It is in better condition than the average Accord of the same vintage and mileage12-25LO 12 - 3Nave BuyerTwo kinds of cars: good cars and lemonsOwners know what kind they haveBuyers cant determine a cars qualityBuyers are risk neutralWhat would the buyer offer for a used car?Expect
27、ed value of a car is(0.90) ($10,000) + (0.10) ($6,000) = $9,600The buyer gets a lemonGood CarsLemonsProbability90%10%Value$10,000$6,00012-26LO 12 - 4Credibility ProblemParties gain if they find a way to communicate information truthfullyIf Jane can convince Tom her Miata is in excellent condition, T
28、om will buyStatements are not credibleJane offers Tom a six-month warranty on all car defects at the time of purchaseA warranty for a lemon would cost more than the economic surplus gainedOnly sellers of good quality cars would offer the warranty12-27LO 12 - 4The Costly-to-Fake PrincipleTo communica
29、te information credibly, a signal must be costly or difficult to fakeSellers have an incentive to exaggerate the quality of their productBuyers value objective information about quality12-28LO 12 - 4Costly SignalsTelevision advertising is expensiveIn print advertising, As seen on TV signals a compan
30、ys commitment to its productPotential signal of qualityEducational institutions brands and students grades signal qualityAn A+ student from MIT is more likely to be offered a job than a C student from an average academic institution12-29LO 12 - 4Conspicuous ConsumptionChoose a lawyerLawyer A wears i
31、nexpensive suits and drives a 10-year old Dodge NeonLawyer B wears custom-tailored suits and drives a new BMW 745iNo other information is availableConspicuous consumption signals successChoose Lawyer B . and pass on Ben Matlock!12-30LO 12 - 4Statistical DiscriminationStatistical discrimination uses
32、group characteristics to infer individual characteristicsCan be applied to people as well as to goods and servicesResults from observed differences between groupsExampleThis candidate for employment is in her late twentiesWomen have babies in their late twenties This candidate will have a baby in th
33、e next few yearsHigh cost compared to other candidates12-31LO 12 - 4Dangerous DriversMen under 25 years of age pay more than other drivers for auto insuranceExpected cost of insuring a driver depends the probability and size of claimsIndividual assessments are not possibleRates are based on demograp
34、hic groups and the claim history of those groupsIndividual rates are adjusted upward as more information becomes available12-32LO 12 - 4Adverse SelectionAdverse selection occurs because insurance tends to be purchased more by those who are most costly for companies to insureInsurance is most valuabl
35、e to those with many claimsAdverse selection increases insurance premiumsReduces attractiveness of insurance to low-risk customersBest insurance risk customers opt outRates increaseRepeat12-33LO 12 - 4Moral HazardMoral hazard is the tendency of people to expend less effort protecting insured goodsPe
36、ople take more risk with insured goods or activitiesDeductibles give policy holders an incentive to be more cautiousSuppose a car owner has a $1,000 deductible policyThe owner pays the first $1,000 of each claimStrong incentive to avoid accidentsClaims less than $1,000 are not reportedInsurance prem
37、iums go down12-34LO 12 - 4Disappearing Political DiscourseDisappearing political discourse theory holds that politicians who support a policy will remain silent to avoid being misunderstoodOpposing the death penalty could be interpreted vy voters as being soft on crimeNo necessary relationship betwe
38、en the twoAssumes voters implicitly assign a position to a politician who has not made public statements12-35LO 12 - 4Politicians and the Death PenaltyArguments against the death penaltyExpensive relative to life in prison without paroleIrreversible for people later found innocentDoes not deter capi
39、tal crimesPoliticians avoid taking a public position on capital punishment12-36LO 12 - 4Politicians and the Death PenaltyVoters want politicians are tough on crimeBroader issue than the death penaltyTwo groups of politicians: tough on crime and soft on crimeVoters use information about a politicians
40、 views on the death penalty to infer the politicians stand on crime12-37LO 12 - 4Politicians and the Death PenaltyPoliticians tough on crime and opposed to capital punishment lose votesThey have an incentive to remain silentMove to blue boxProbability that a politician in the red box is tough on cri
41、me decreasesMore defectionsPublic statements do not accurately reflect aggregate views of politicians on capital punishmentFavor Death Penalty PLUS Remain Silent95% tough on crimeOppose only the Death PenaltyOppose Punishing Criminals80% tough on crime12-38LO 12 - 4Legalized DrugsLaws against buying
42、 and selling certain substances are intended to reduce the harm to society from drug useLaws have a costPrice of illegal drugs increasesAddicts commit crimes to pay for drugsDiverts people from productive employmentExternalities of turf battlesHigh cost to law enforcement, legal, and prison systems
43、12-39LO 12 - 4Legalized DrugsLegalization solves most problemsWith lower drug prices, quantity demanded may increaseNot supported by evidence in UK and NetherlandsAn outspoken supporter is seen by voters as more likely to be crazy than an outspoken opponentRational supporters do not speak outRational Rational OpponentOpponentRational Rational SupporterSupporterCrazy OpponentCrazy OpponentCrazy SupporterCrazy SupporterOpponentsOpponentsSupportersSupporters12-40LO 12- AllThe Economics of InformationTheEnd谢谢您的聆听！期待您的指正！
