麻省理工发展经济学讲义.pdf

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1、1Agriculture:Theefficiencyoflanduse•Shareofagricultureinemploymentiscloseto50%fortheworldasawhole(50%inChina,57%inIndia).•Islandusedefficiently?1.0.1Farmsizeandproductivity:observedrela-tionship•Farmsizeproductivitydifferences:seetable.•Profit-Wealthrationandweathervariability(mon-soonoutsetisameasur

2、eoftheriskfacedbythefarmer):seefigure—TheProfit-Wealthratioisalwaysgreaterforsmallfarmers—Smallfarmers’profitsarehurtmuchmorebyuncertaintythanlargefarmers’1.0.2Whyisthissurprising?•Argumentsforincreasingreturns(theoppositere-lationship)—Technologywithfixedcosts(tractors,etc..)—Largerfarmershavebett

3、eraccesstocapital—Largerfarmershavebetteraccesstopoliti-callyallocatedinputs(evidencefromAfricainabookbyBates“MarketandstatesintropicalAfrica”).—Thebestfarmerwillhavemoreland...•Mitigatingfactors:—Rentalmarketsinfarmmachinery—Technologicalchangeinnotveryrapid.Savi-nessnotthatimportant.1.0.3What

4、couldbegoingon:Argumentsforde-creasingreturns•—Agencyproblems:largefarmsarecultivatedbyhiredlabor,whichhasfewerincentivetoworkhard.Smallfarmsareownercultivated.⇒Redistributinglandwillcreatemoreownercultivatedlandwhichwillbemoreproductive.—Butwhycannottheownerofthelandnotgivetherightincentivetot

5、hefarmers?1.0.4Differentpotentialexplanationsfortheob-servedinverseproductivityrelationship:•Differencesinlandquality•Differencesinfarmercharacteristics•IncentiveProblemsProblemwiththeobservedrelationship:allofthiscouldbegoingon...Howcanweseparatethesedif-ferenteffects.1.0.5Evidence:StudybyBiswange

6、randRosen-zweig•UsingICRISATdata:verydetailedpanel(repeatedobservationforeveryhousehold)datafromIndia.•Someindividualscultivatebothanowner-operatedplotandarentedplot.•BiswangerandRosenzweigcomparetheinputstheyapplyontheirownplotandtherentedplots,andtheoverallproductivityofbothplots.Πij=α+βRij+η

7、i+υij,•whereΠijisfarmer’sioutcome(profit,invest-ment)onplotj,andRijindicatewhethertheplotisrented.ηiistheunoberved(butfixed)characteristicsofthefarmers(riskaversion,qual-ity,etc...).WethinkthatηiandRijmaybecorrelated,but,foraminute,