曼昆经济学原理微观部分第6章

Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.Supply,Demand,andGovernmentPoliciesuInafree,unregulatedmarketsystem,marketforcesestablishequilibriumpricesandexchangequantities.uWhileequilibriumconditionsmaybeefficient,itmaybetruethatnoteveryoneissatisfied.uOneoftherolesofeconomistsistousetheirtheoriestoassistinthedevelopmentofpolicies.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.供给、需求与政府政策u在一个自由、无管制的市场系统中，市场力量实现均衡价格和均衡交易量。u这种均衡结果也许是有效的，但并不是每个人对此都感到满意。u经济学家的作用之一就是利用他们的理论帮助制定政策。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ControlsonPrice...价格控制…uAreusuallyenactedwhenpolicymakersbelievethemarketpriceisunfairtobuyersorsellers.当政策制定者认为市场价格对买者或卖者不公平时，往往实行价格控制。uResultingovernment-createdpriceceilingsandfloors.这就促使政府实行价格上限和价格下限政策。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ControlsonPrice...价格控制…PriceCeiling价格上限uAlegallyestablishedmaximumpriceatwhichagoodcanbesold.可以出售一种物品的法定最高价格。PriceFloor价格下限uAlegallyestablishedminimumpriceatwhichagoodcanbesold.可以出售一种物品的法定最低价格。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.HowPriceCeilingsAffectMarketOutcomesnTwooutcomesarepossiblewhenthegovernmentimposesapriceceiling:äThepriceceilingisnotbindingifsetabovetheequilibriumprice.äThepriceceilingisbindingifsetbelowtheequilibriumprice,leadingtoashortage.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.价格上限如何影响市场结果当政府实行价格上限时，可能出现两种价格：如果价格上限高于均衡价格，价格上限没有限制作用。如果价格上限低于均衡价格，价格上限对市场有限制作用。APriceCeilingThatIsNotBinding...$43QuantityofIce-CreamCones0PriceofIce-CreamConeDemandSupplyPriceceilingEquilibriumprice100Equilibriumquantity没有限制作用的价格上限...$43冰激凌蛋卷的数量0冰激凌蛋卷的价格需求供给价格上限均衡价格100均衡数量APriceCeilingThatIsBinding...$3QuantityofIce-CreamCones0PriceofIce-CreamCone2DemandSupplyEquilibriumpricePriceceilingShortage125Quantitydemanded75Quantitysupplied有限制作用的价格上限...$3冰激凌蛋卷的数量0冰激凌蛋卷的价格2需求供给均衡价格价格上限短缺125需求量75供給量Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.HowPriceCeilingsAffectMarketOutcomesnEffectsofPriceCeilingsnAbindingpriceceilingcreates...shortagesbecauseQDQS.uExample:Gasolineshortageofthe1970snonpricerationinguExamples:Longlines,DiscriminationbysellersHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.价格上限如何影响市场结果n价格上限的作用n有限制作用的价格上限造成...短缺，因为QDQS.u例子:70年代的汽油短缺非市场价格方式配给u例子:排长队,卖者歧视Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.LinesattheGasPumpIn1973OPECraisedthepriceofcrudeoilinworldmarkets.Becausecrudeoilisthemajorinputusedtomakegasoline,thehigheroilpricesreducedthesupplyofgasoline.Whatwasresponsibleforthelonggaslines?Economistsblamegovernmentregulationsthatlimitedthepriceoilcompaniescouldchargeforgasoline.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.加油站前的长队1973年，石油输出国组织（OPEC)提高了世界石油市场的原油价格。由于原油是用于生产汽油的主要投入，较高石油价格减少了汽油供给。谁对加油站前的长队负责？经济学家把它归咎于限制石油公司对汽油可以收取的价格的政府管制。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ThePriceCeilingonGasolineIsNotBinding...汽油的价格上限没有限制性…$4P1QuantityofGasoline汽油数量0PriceofGasoline汽油价格Q1Demand需求Supply供给Priceceiling价格上限1.Initially,thepriceceilingisnotbinding...1.原来，价格上限没有限制性…Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ThePriceCeilingonGasolineIsBinding...P1QuantityofGasoline0PriceofGasolineQ1DemandS1PriceceilingS22.…butwhensupplyfalls...P23.…thepriceceilingbecomesbinding...4.…resultinginashortage.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.汽油的价格上限有限制性...P1汽油数量0汽油价格Q1需求S1价格上限S22.…但当供给减少时...P23.…价格上限变为限制性的...4.…导致短缺。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.RentControlintheShortRunandLongRunuRentcontrolsareceilingsplacedontherentsthatlandlordsmaychargetheirtenants.uThegoalofrentcontrolpolicyistohelpthepoorbymakinghousingmoreaffordable.uOneeconomistcalledrentcontrol“thebestwaytodestroyacity,otherthanbombing.”Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.短期中和长期中的租金控制u租金控制——房东能向房客收取的租金上限。u这一政策的目的是帮助穷人更能租得起住房。u一位经济学家称租金控制是“除了轰炸之外毁灭一个城市的最好方法”。Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.RentControlintheShortRun...QuantityofApartments0RentalPriceofApartmentDemandSupplyControlledrentShortageSupplyanddemandforapartmentsarerelativelyinelasticHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.短期的租金控制...公寓数量0公寓租金价格需求供给受控制的租金短缺供给与需求都相对缺乏弹性Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.RentControlintheLongRun...QuantityofApartments0RentalPriceofApartmentDemandSupplyControlledrentShortageBecausethesupplyanddemandforapartmentsaremoreelastic...…rentcontrolcausesalargeshortageHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.长期的租金控制...公寓数量0公寓租金价格需求供给受控制的租金短缺因为供给和需求更富有弹性……租金控制导致大量短缺Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.HowPriceFloorsAffectMarketOutcomesWhenthegovernmentimposesapricefloor,twooutcomesarepossible.uThepricefloorisnotbindingifsetbelowtheequilibriumprice.uThepricefloorisbindingifsetabovetheequilibriumprice,leadingtoasurplus.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.价格下限如何影响市场结果当政府实行价格下限时，可能出现两种价格：如果价