社会成本问题(The-Problem-of-Social-Cost)

TheProblemofSocialCostRonaldH.CoaseRonaldH.CoaseisProfessorofEconomicsattheUniversityofChicago.ThispaperisfromtheJournalofLawandEconomics(October1960).I.TheProblemtoBeExamined1Thispaperisconcernedwiththoseactionsofbusinessfirmswhichhaveharmfuleffectsonothers.Thestandardexampleisthatofafactorythesmokefromwhichhasharmfuleffectsonthoseoccupyingneighboringproperties.Theeconomicanalysisofsuchasituationhasusuallyproceededintermsofadivergencebetweentheprivateandsocialproductofthefactory,inwhicheconomistshavelargelyfollowedthetreatmentofPigouinTheEconomicsofWelfare.Theconclusionstowhichthiskindofanalysisseemstohaveledmosteconomistsisthatitwouldbedesirabletomaketheownerofthefactoryliableforthedamagecausedtothoseinjuredbythesmoke,oralternatively,toplaceataxonthefactoryownervaryingwiththeamountofsmokeproducedandequivalentinmoneytermstothedamageitwouldcause,orfinally,toexcludethefactoryfromresidentialdistricts(andpresumablyfromotherareasinwhichtheemissionofsmokewouldhaveharmfuleffectsonothers).Itismycontentionthatthesuggestedcoursesofactionareinappropriate,inthattheyleadtoresultswhicharenotnecessarily,orevenusually,desirable.II.TheReciprocalNatureoftheProblemThetraditionalapproachhastendedtoobscurethenatureofthechoicethathastobemade.ThequestioniscommonlythoughtofasoneinwhichAinflictsharmonBandwhathastobedecidedis:howshouldwerestrainA?Butthisiswrong.Wearedealingwithaproblemofareciprocalnature.ToavoidtheharmtoBwouldinflictharmonA.Therealquestionthathastobedecidedis:shouldAbeallowedtoharmBorshouldBbeallowedtoharmA?Theproblemistoavoidthemoreseriousharm.Iinstancedinmypreviousarticle2thecaseofaconfectionerthenoiseandvibrationsfromwhosemachinerydisturbedadoctorinhiswork.Toavoidharmingthedoctorwouldinflictharmontheconfectioner.Theproblemposedbythiscasewasessentiallywhetheritwasworthwhile,asaresultofrestrictingthemethodsofproductionwhichcouldbeusedbytheconfectioner,tosecuremoredoctoringatthecostofareducedsupplyofconfectioneryproducts.Anotherexampleisaffordedbytheproblemofstrayingcattlewhichdestroycropsonneighboringland.Ifitisinevitablethatsomecattlewillstray,an1Thisarticle,althoughconcernedwithatechnicalproblemofeconomicanalysis,aroseoutofthe.studyofthePoliticalEconomyofBroadcastingwhichIamnowconducting.Theargumentofthepresentarticlewasimplicitinapreviousarticledealingwiththeproblemofallocatingradioandtelevisionfrequencies(TheFederalCommunicationsCommission,J.LawandEcon.,II(19591)butcommentswhichIhavereceivedseemedtosuggestthatitwouldbedesirabletodealwiththequestioninamoreexplicitwayandwithoutreferencetotheoriginalproblemforthesolutionofwhichtheanalysiswasdeveloped.2'Coase,TheFederalCommunicationsCommission,J.LawandEcon.,II(1959),26-27.-2-increaseinthesupplyofmeatcanonlybeobtainedattheexpenseofadecreaseinthesupplyofcrops.Thenatureofthechoiceisclear:meatorcrops.Whatanswershouldbegivenis,ofcourse,notclearunlessweknowthevalueofwhatisobtainedaswellasthevalueofwhatissacrificedtoobtainit.Togiveanotherexample,ProfessorGeorgeJ.Stiglerinstancesthecontaminationofastream3.Ifweassumethattheharmfuleffectofthepollutionisthatitkillsthefish,thequestiontobedecidedis:isthevalueofthefishlostgreaterorlessthanthevalueoftheproductwhichthecontaminationofthestreammakespossible.Itgoesalmostwithoutsayingthatthisproblemhastobelookedatintotalandatthemargin.III.ThePricingSystemwithLiabilityforDamageIproposetostartmyanalysisbyexaminingacaseinwhichmosteconomistswouldpresumablyagreethattheproblemwouldbesolvedinacompletelysatisfactorymanner:whenthedamagingbusinesshastopayforalldamagecausedandthepricingsystemworkssmoothly(strictlythismeansthattheoperationofapricingsystemiswithoutcost).Agoodexampleoftheproblemunderdiscussionisaffordedbythecaseofstrayingcattlewhichdestroycropsgrowingonneighboringland.Letussupposethatafarmerandacattle-raiserareoperatingonneighboringproperties.Letusfurthersupposethat,withoutanyfencingbetweentheproperties,anincreaseinthesizeofthecattle-raiser'sherdincreasesthetotaldamagetothefarmer'scrops.Whathappenstothemarginaldamageasthesizeoftheherdincreasesisanothermatter.Thisdependsonwhetherthecattletendtofollowoneanotherortoroamsidebyside,onwhethertheytendtobemoreorlessrestlessasthesizeoftheherdincreases,andonothersimilarfactors.Formyimmediatepurpose,itisimmaterialwhatassumptionismadeaboutmarginaldamageasthesizeoftheherdincreases.Tosimplifytheargument,Iproposetouseanarithmeticalexample.Ishallassumethattheannualcostoffencingthefarmer'spropertyis$9andthatthepriceofthecropis$1perton.Also,Iassumethattherelationbetweenthenumberofcattleintheherdandtheannualcroplossisasfollows:CropLossperNumberinHerdAnnualCropLossAdditional(Steers)(Tons)Steer(Tons)111Z323634104Giventhatthecattle-raiserisliableforthedamagecaused,theadditionalannualcostimposedonthecattle-raiserifheincreasedhisherdfrom,say,twotothreesteersis$33G.J.Stigler,TheTheoryofPrice,p.105(1952).-3-andindecidingonthesizeoftheherd,hewilltakethisintoaccountalongwithhisothercosts.Thatis,,hewillnotincreasethesizeoftheherdunlessthevalueoftheadditionalmeatproduced(assumingthatthecattle-raiserslaughterst