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PolicyResearchWorkingPaper10449

WeightingJusticeReformCosts

andBenefitsUsingMachineLearning

andModernDataScience

ChrisMahony

MatthewManning

GabrielWong

SocialSustainabilityandInclusionGlobalPractice

May2023

ProducedbytheResearchSupportTeam

PolicyResearchWorkingPaper10449

Abstract

paperidentifieshowsubgroupsintheinterventiondis-playdifferentbehavioraladjustmentsacrossthereferenceperiod,revealingtheheterogeneousdistributionofcostsandbenefits.Finally,thepaperdiscussesthenextversionofthecost-benefitanalysisapp,whichincorporatesanartificialintelligence-drivencomponentthatreintegratesindividualcost-benefitanalysisprojectsusingmachinelearningandothermoderndatasciencetechniques.Thepaperarguesthattheappenhancescost-benefitanalysis,developmentoutcomes,andpolicymakingefficiencyforoptimalprioritizationofcriminaljusticeresources.Further,theappadvancesthepolicyaccessibilityofenhanced,socialgroup-specificdata,illuminatingoptimalpolicyorientationformoreinclusive,just,andresilientsocietaloutcomes—anapproachwithpotentialacrossbroaderpublicpolicy.

Cantheimpactofjusticeprocessesbeenhancedwiththe

inclusionofaheterogeneouscomponentintoanexisting

cost-benefitanalysisappthatdemonstrateshowbenefactors

andbeneficiariesareaffected?Suchacomponentrequires

(i)movingbeyondthetraditionalcost-benefitconceptual

frameworkofutilizingaverages,(ii)identificationofsocial

grouporpopulation-specificvariation,(iii)identificationof

howjusticeprocessesdifferacrossgroups/populations,(iv)

distributionofcostsandbenefitsaccordingtotheidenti-

fiedvariations,and(v)utilizationofempiricallyinformed

statisticaltechniquestogainnewinsightsfromdataand

maximizetheimpactforbeneficiaries.Thispaperoutlines

amethodforcapturingheterogeneity.Thepaperteststhe

methodandthecost-benefitanalysisonlineappthatwas

developedusingprimarydatacollectedfromadevelop-

mentalcrimepreventioninterventioninAustralia.The

ThispaperisaproductoftheSocialSustainabilityandInclusionGlobalPractice.ItispartofalargereffortbytheWorldBanktoprovideopenaccesstoitsresearchandmakeacontributiontodevelopmentpolicydiscussionsaroundtheworld.PolicyResearchWorkingPapersarealsopostedontheWebat/prwp.Theauthorsmaybecontactedatcmahony@.

ThePolicyResearchWorkingPaperSeriesdisseminatesthefindingsofworkinprogresstoencouragetheexchangeofideasaboutdevelopmentissues.Anobjectiveoftheseriesistogetthefindingsoutquickly,evenifthepresentationsarelessthanfullypolished.Thepaperscarrythenamesoftheauthorsandshouldbecitedaccordingly.Thefindings,interpretations,andconclusionsexpressedinthispaperareentirelythoseoftheauthors.TheydonotnecessarilyrepresenttheviewsoftheInternationalBankforReconstructionandDevelopment/WorldBankanditsaffiliatedorganizations,orthoseoftheExecutiveDirectorsoftheWorldBankorthegovernmentstheyrepresent.

WeightingJusticeReformCostsandBenefitsUsingMachineLearningandModern

DataScience

ChrisMahony1*,MatthewManning2*,GabrielWong3*

Keywords:justicereform;cost-benefitanalysis;machinelearning;datascience;justiceprocesses;heterogeneity

*ThispaperexclusivelyreflectstheviewsoftheauthorsanddoesnotnecessarilyrepresentthoseoftheWorldBanknoritsBoardofDirectors.TheauthorsthankVaralakshmiVemuru,JoseCuesta,RohiniSrihari,JamesBrumby,BarryMaher,PatrickBarron,andAlyRahimforusefulfeedbackandsuggestions.Allremainingerrorsaresolelytheresponsibilityoftheauthors.

1WorldBankGroup;PeloriaP.B.C;

2DepartmentofSocialandBehavioralSciences,CityUniversityofHongKong;

3ANUCentreforSocialResearchandMethods,TheAustralianNationalUniversity

2

Introduction

ThejointUnitedNations-WorldBankflagshipreport,'PathwaysforPeace'(UnitedNationsandWorldBank,2018),citesgrievancessurroundingsocialgroup-specificexclusionfromaccesstojusticeandsecurityasoneoffourarenasofsocialcontestthatinformtheriskofviolence.

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TheWorldBankhasdevelopedanalyticaltoolsforidentifyingthepoliticaleconomyandefficacyofgovernanceandjusticereformincludingtherelationshipbetweenjusticesectorpolicyandprogrammaticapproachesandtheWorldBank’stwingoalsofreducingextremepovertyanddrivingsharedprosperity.

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Toachievetheabovegoals,acomprehensiveeconomicframeworkisrequiredfortracinghowpublicpolicyprocessesortheirsubstantiveconsequencesvaryacrossindividualsandcommunities.Currentlyinthisspace,however,cost-benefitanalysis(CBA)reliesontheaveragetreatmenteffect(ATE),whichdoesnotadequatelyunpackthecontextualvariationsthatmoderateeconomicoutcomesacrossaffectedcommunitiesorsub-groupswithincommunities.

Thispaperconsidersthepolicyquestionspecifictothejusticesector:CantheimpactofjusticeprocessesbeenhancedwiththeinclusionofaheterogenouscomponentintoanexistingCBAAPPthatdemonstrateshowbenefactorsandbeneficiariesareaffected?Thedevelopmentofsuchaframeworkrequires:(i)movingbeyondthetraditionalcost-benefitconceptualframeworkofutilizingaverages(i.e.ATE);(ii)identificationofvariationordifferencesbetweengroupsorpopulations(e.g.individualactorattributes,politicalstructures,institutions);(iii)identificationofhowjusticeprocessesdifferacross

groups/populations;(iv)distributionofcostsandbenefitsaccordingtotheidentifiedvariations(i.e.heterogenousimpactspecifictothenatureofjusticepolicy/interventionorthecontextinwhichthepolicy/interventionoccurs);and(v)utilizationofempiricallyinformedstatisticaltechniquestogainnewinsightsfromdataandmaximizeimpacttobeneficiaries.

1Thethreeother‘a(chǎn)renas’ofsocietalcontestationassociatedwithsocialgroupspecificgrievancessurroundingexclusionincludeaccesstopoliticalpower,accesstolandandresources,andaccesstopublicservices.SeeUnitedNations&WorldBank.(2018).PathwaysforPeace:InclusiveApproachestoPreventingViolentConflict.WorldBank.WashingtonDC.

2SeeanalyticalapproachesemployedbytheWorldBank:

/en/topic/governance/brief/justice-rights-and-public-safety

.Andprecedingapproaches:Justicediagnostics

(/curated/en/803711468338346161/pdf/437070WP0Box3210March0200701P

UBLIC1.pdf)

,Governancediagnostics

(/archive/website00818/WEB/DIAGNOST.HTM

).

3

Individually,thesepointsarenotnovel,butitistheirintegrationthatprovidesnewempiricalopportunities.

ThePathwaysforPeacereporttakesimportantstepsinidentifyingthedeliveryofeducation,healthcare,water,sanitation,justiceandsecurityas“theglue”bindingstateandsociety(MillikenandKrause,2002)viathebasicminimumcitizensexpectinordertoacceptstateauthority(Gilley,2009).However,thereportacknowledgesthecomplexityoftherelationshipbetweenservicedeliveryandlegitimacy(Brinkerhoffetal.,2012;SacksandLarizza,2012;StelandAbate,2014;Mcloughlin,2015;FiskandCherney,2017).Statelegitimacydependsonpublicexpectations,whichareinformedbypriorexperiences(Nixonetal.,2017),geography,identity,andculture(Sturgeetal.,2017).ThereportacknowledgestheSustainableDevelopmentGoals(SDG16.3)topromotetheruleoflawandensureequalaccesstojusticeforall(UnitedNationsandWorldBank,2018).Thereportemphasizesthatdevelopmentapproachesmustidentifyhow,notonlywhy,justiceprocessesandoutcomesdiscriminate,orareperceivedtodiscriminate,againstcertaingroups(UnitedNationsandWorldBank,2018).Beyondestablishmentofframeworksidentifyinghowprocessestreatgroupsdifferently,developmentactorsmustgrapplewithhowtomostequitablydeployfiniteresourcestochangethatunequaltreatment.Forexample,decisionsregardingtheequitabledeploymentoffiniteresourcesmaybeinfluencedbystatic(e.g.ethnicity)anddynamic(e.g.socio-economicstatus)indicatorsthatrecognizegroupdifferenceswithinacommunity.IncorporatingthisdataintoCBAenablesidentificationofhowjusticeprocessestreatdifferentgroupsandtheconsequences(economicandsocial)forthosegroups.

Identifyingandcommunicatingthedynamicinteractionsoffactorsassociatedwiththeindividualandnetcostsandbenefits(includingtheirinclusivity)ofpolicychangeincreasesscopeforinformedcitizenparticipation–enhancingsocialinclusionandprocesslegitimacy.Socialinclusionandprocesslegitimacyconstitutetwooffour(socialresilienceandsocialcohesionbeingtheothers)clustersoffactorscomprisingtheconceptof‘socialsustainability’,whichisassociatedwithincreasedpercapitaincomeandreducedpoverty(CuestaLeivaetal(2022).

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3Wenotetheabsenceofconsensusontheconceptordefinitionofsocialsustainability.However,weacknowledgethefourCuestaLeivaetal(2022)-identifiedclustersofidentifiedsocialsustainabilityfactors.Oneofthosefactorsis‘processlegitimacy’,describedastheextenttowhichpolicyandimplementationprocesses’engagementwithlocalnormsandvalues,andtheirreconciliationofopposingviewpointsdriveperceptionsof

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Totakeforwardaframeworkthatalsoappropriatelyprioritizestheuseoffiniteresources,thecostsandbenefitsofpolicyoptionsmustbeproperlyweighedwithinthecontextofthe“dynamicinteractionofactors,institutions,andstructuralfactorsovertime”(UnitedNationsandWorldBank,2018).Toolsnecessarytoachievethisoutcomemustdriveoptimaljusticesectordecisionsinasystematic,data-informed,andresource-efficientway,includingdrawingonWorldBankanalyticalproducts.Theseproductsincludelegalneedssurveys,FunctionalReviews,InstitutionalandExpenditureReviews,JusticeforthePoordisputeresolutionanalytics,theDoingBusinesssurvey(whichincludesaQualityofJudicialProcessIndex),TheWomen,BusinessandtheLawindex,andtheDataandEvidenceforJusticeReformplatform.Bydrawingtogetherdatafromallanalyticalprocesses,scopeforcomparisonofvariousjustice-relateddatasetsisenabled.

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Mostimportantly,theanalyticalapproachesassistinidentifyingthevariouselementsofjusticeprocesseswhosecostsandbenefitsmaythenbetraced.

EarlyCBAtools,suchastheWashingtonStateInstituteofPublicPolicy's(WSIPP)Benefit-CostTool(AosandDrake,2010)andtheManningCostBenefitTool(MCBT)(CollegeofPolicing,2022),weredevelopedtosupportanevidence-basedpolicingapproach.MorerecentdevelopmentshavebeenundertakenbyManningandWong,whichrepresentsanextensionoftheabove-mentionedMCBT(nowadoptedbytheCollegeofPolicingUK),arebeginningtoincopporatemachinelearningandartificialintelligence,includingthedevelopmentofCBTAPP(Manning,2018)and‘Smart’CBTs(Manningetal.,2018),takeimportantstepstowardsrobustandtime-sensitiveanalyticalmethods.Thesetools(currentlyinvariousstagesofdevelopment),whichhavebeenvalidatedusingarangeofcrimedata,

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provideaframeworkwithsystematicdatamanagementcapacitythatenablesuserinput

decisionsassufficientlyfair,credible,andacceptable.Asecondis‘socialinclusion’whichistheextenttowhichaccesstobasicservicesandmarketsaswellaspolitical,social,andculturalspacesareenabledinorderforparticipationinsocietywithagencyanddignity(CuestaLeiva2022).Tomeasurethefour(socialinclusion,socialresilience,socialcohesion,andprocesslegitimacy)componentsof‘SocialSustainability’theycite,(1)for‘socialinclusion’,laborparticipation,financialinclusion,publicserviceaccessibility,andpoliticalparticipation;(2)for‘socialresilience’,theabilitytosave,incomediversity,shock-responsiveassets,foodsecurityandmigratorymobility;(3)for‘socialcohesion’,interpersonalandinstitutionaltrust,violencelevels,anddemocraticandcivicparticipation,and;(4)for‘processlegitimacy’,ruleoflawmeasurements,corruptionlevels,separationofpower,objectivityandequality(includingaccessibility)oflaw/regulationapplication,andphysicalsecurity.

4SeeanalyticalapproachesemployedbytheWorldBank:

/en/topic/governance/brief/justice-rights-and-public-safety

.

5ThecurrentversionofMCBT,withcrime-relateddataasexamples,canbefoundat:

.au/CD-AV/

.Newexamplesareregulalryuploadedtodemonstratethecapabilityofthetooltobeadoptedindifferentcontexts.Foraccess,pleasecontact

matthew.manning@.au

.

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supportandeconomicanalysis.Thetoolscancaptureheterogeneityacrosssocialgroupsinformingjusticereforminvestmentdecisionsthatbestmanageandmitigatesocialgroupspecificgrievanceswhilemaximizingeconomicconsequence.The‘SmartCBT’,oncefullydeveloped,willmovebeyondorthodoxtechniquesbydevelopingadatabasesystemthatsecurelystoresandde-identifiesprojectdata.Thatdataisthenredeployedusingarangeofmachinelearninganddatasciencetechniques.

Inthecontextofjusticereforminvestment,theSmartCBT,coupledwiththeproposedadditiontothetooloutlinedinthispaper,willbeenhancedwiththeinclusionofnewfeatures:(i)analysisidentifyingmethodsofreform;(ii)policyadjustment;and/or(iii)capacityenhancementthatoptimizestheeconomicbenefitstoasocietyasawhole.

Thefirstchallengeistowhatextenttheenhancedtooldiscussedaboveselectsthemostefficientoption/savailablewhileaccountingforheterogenoustreatmenteffects?Traditionally,CBAfocusesonaveragebenefits(e.g.averagetreatmenteffects(ATE))andaveragecosts.Thesemetricsarenotalwaysadequatelydisaggregatedamong

groups/communities,underminingscopeforevaluationofinterventions’effectsonhorizontalinequalities(socialinclusion).Heterogeneoustreatmenteffectsand/orcostsaremostoftenpresentbutunaccountedfor,potentiallydiminishinglegitimacy,particularlyforsocialgroupsthatexperiencedisproportionalynegativeeffects.Theretentionofbigdataenablesgreatercapacitytoundertakemore‘comprehensive’,ratherthan‘narrow’CBA.Thismeansthatefficiencypotentialishiddeninboththeefficacyandimplementationofpublicandprivateprograms,ifpoliciescanbetargetedatthosewho,netofcosts,benefitthemostand/oraremostvulnerable.Here,wespeakintermsofdisproportionatesocialgroupaccesstopublicgoodssuchashealth,electricity,justiceorotherservices(UnitedNationsandWorldBank,2018).However,theprimarycontributionenabledbythisworkisthepotentialforadvancedCBAtosupportex-antepolicyandprogrammaticanalysisalongsideorthodoxDevelopmentImpactEvaluationsand/orPovertyandSocialImpactAnalyses.

ThispaperexplorestheutilityoftheCBAAPPforajusticesectorcase.However,contextualfactorsidentifiedinthisorothersmartCBAscouldbemorereadilydrawnupontotestotherinterventionsacrossthepolicyspectrum,includingforheterogenousimpact.Thedevelopmentofsuchcapacity,itishypothesized,wouldsignificantlyreducehumanandmaterialcostobstaclesassociatedwithrepeatedindividualCBAsfordifferentjusticeprocessesorotherpublicpolicyareas.Re-usingtheCBAAPPwouldre-vetcontextualdatarepresentativienessalongsideenablingmoreefficientCBAacrossthepublicpolicyspectrum.

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Inthefollowingsectionsweconsiderthestateoftheliteratureandpracticeofcost-benefitanalysisbeforeintroducingasystemticmethodforweighingcostsandbenefits,includingwithdisaggregationtodifferentsocialgroups.Wethenintroducethecaseandmethodfortestingthisapproach,includinginidentifyingheterogeneousdistributionofcostsandbenefits.WethenintroduceanAI-drivencomponentthatreintegratesindividualCBAprojects,enhancing,weargue,CBA,developmentoutcomes,andpolicymakingefficiencyforoptimalprioritizationofcriminaljusticeresources.Wediscussourresultsandthepotentialforpublicpolicyapplicationtobetterilluminatesocialgroupspecificcostsandbenefits,andidentifyoptimallyinclusiveandjustpolicysettings.

1.Cost-BenefitAnalysisLiterature

Theliteratureoutliningexistingknowledgeanddatagapsthathavehistoricallyconstrainedreliablecost-benefitanalysisinthejusticefieldisscattered.Werecognizethattheliteratureonjusticesector-specificCBAisdeveloping,withmuchscopeforadvanceasthedatailluminatinghumanbehaviorbecomesmorerepresentative,reliable,andaccessible.AmartyaSennotesthehistoricallynarrownatureofanalysissolelythroughmarketvalues,whichomitsocialchoicesthatenablefreedomofvaluationandincreasedinformationalinputs(Sen,2000).Harleyet.aldefinenarrowCBAs,whichtheyobserveasmorecommonlyemployed,ascomprising“directtangiblebenefitsandcosts”resultingfromtheprogrammaticorpolicychange(Harleyetal.,2019).

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Harleyet.aldefine‘comprehensive’CBAasaccountingfordirecttangiblebenefitsandcostsplus“amoreextensiveaccountingoftheindirecteconomicbenefitstoallthoseaffected”,including“benefitstoindividuals,thejusticesystem,theeconomyandsociety”(Harleyetal.,2019).Diversedatasetsthatcaptureheterogeneity,whendrawnuponviamodernartificialintelligencetechniques,empowerdatamanagementsystemsanddevelopmentpractitionerstodelivermorecomprehensiveCBAs.

Developmentactorsplayanimportantroleinidentifyingoptimalmethodsforjustifyingandprioritizingscarcejusticesectorresourcesthatbenefitsocietyatlargewhileaccountingfordisproportionatecostsandbenefits(bothobjectiveandsubjectiveinnature).Importantly,thisrolemustalsofullyconsidersocialimplicationsincludingintangiblecostsandbenefits.TheWorldBankisenhancingandupholdingahighleveloftransparencyandintegritywithregardstosafeguardinginvestmentthatisefficientandtransparent.CBAtools

6TheirconsiderationofCBAisspecifictoLegalAid.

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haveanimportantroletoplayinadvancingthepreventionofintegritycrimes.Approaches,reforms,andenforcementcapacityrelatingtoimproperconductsuchasimproprietiessurroundingtenderingprocesses(particularlypublicsectorcontracts),bribery,andfinancialsectorintegrity(FinancialActionTaskForce(onMoneyLaundering)(FATF)compliance),forexample,maybestbeprioritizedviaobjectiveobservationofcostsandbenefits.

Engagingtheeconomicsofaccesstojustice

LikepolicysettingsrelatingtoFATF,aCBTmayalsobeemployedtoidentifybroaderjusticesectorpolicycost-benefitimplications.Evidenceregardinghumandecisionmakingindevelopingcountrycontextsisscarce(WorldBank,2017).TheWorldBankobservesthreeprincipalsinformingunderstandingofhumancognitioninthesecontexts.Firstly,thatmostjudgmentsandchoicesaremadeautomatically,notdeliberatively.Second,peopleoften“thinksocially–theyactandthinkdependentonwhatothersaroundthemdoandthink.Third,individualsshareacommonperspectiveonmakingsenseoftheworldbasedonpersonsinthesocietyaroundthem”(WorldBank,2017).BanerjeeandDuflo(2011)identifytheconstrainedcapacityofthepoortotakealongerviewoftheirlivesbecauseoftheextramentalenergyusedjusttoaddressthemostbasicofneeds,likeshelter,withinaheirachyofneeds(McLeod,2007).Lookingbeyondaheirachyofneedsandrelyingonrandomizedcontroltrialsin18countries,BanerjeeandDuflonotethattheconstrainedmentalenergyofthepoorlimitstheirabilitytoevenenvisageafuture.Failureincriminalorciviljusticeprocessesexaggeratesexclusionbyincreasingobstaclestolow-levelneedslikeshelter.Theopportunitycostfordisproportionatelytime-poorhouseholdsofpursuingjusticeoutcomesexaggeratesbarrierstoaccessingjusticeprocessesandjustoutcomes(Vickery,1977).Inabilitytoaccessjusticeprocessesalsoexaggeratesotherinequalitiesthatrenderthepoortime-poor.Thewealthyenjoychlorinatedwater,regularanddirectlybank-depositedsalariesoftenwithautomaticallydeductedpensionandhealthcarecontributions.Thepoorexpendtimeandscarceresourcestoorganizeandengagejusticeprocessestoobtaintheseitems(BanerjeeandDuflo,2011).ACBTneedstounderstandandrespondtothelogicofhowpoorpeoplecopeindividuallyandcollectivelyinspecificcontexts.Existingmeasuresofaccesstojustice(e.g.theWorldJusticeProjectRuleofLawIndex)(TheWorldJusticeProject,2019)alongsidedatacollectedbygovernmentsanddevelopmentactors,maybeincorporatedintoaCBT.UsingCBAtoolsthatincorporateheterogenousoutcomesisimportantinordertodeterminehowresourcesdirectedtoeliminatebarrierstojusticecanbeefficientlyandeffectivelyallocated.

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Datainfragileandconflict-affectedstatesisscarce.However,legalaidprogramsenjoyparticularsuccessinsituationswherepoliticalspaceforotherformsofjusticesectorsupportislow.Areviewof199legalaidstudiesfoundonlytenthatconsideredlegalaidprogramsin‘notfree’countries,indicatingthescarcityofdataandunderstandingoflegalaidprogramsunderrepressiveregimes(GoodwinandMaru,2017).Scarcedatademandsfurtherresearchinrelationtolegalaidprograms’mediumandlong-termeffects,theirsustainability,theirdevelopmenteffectbeyondtheimmediatelegalneed(includingchangesinagency),andtheuseofaccountabilitymechanisms(includinghumanrightscommissions,ombudsoffices,andpublicinterestlitigation)(GoodwinandMaru,2017).Weknowlittleaboutlegalempowerment,despitethemultitudeofformsitmighttake.Scarceknowledgesurroundingtheenvironmentswherelegalaidprogramsaresuccessful(atnationalorcommunitylevel)demandsresearchthatcodesaccordingtodemography,socialnorms,powerdifferentialsandotherpoliticalcircumstances(GoodwinandMaru,2017).Italsorequiresconsiderationofprogrammaticallyspecificstakeholdersandrisksacrossthemanyformsoflegalaidprogrammingrelatingtomanyinteractionsbetweencitizensandformaljusticesystems,informaljusticesystems,andformalandinformaladministrativeprocesses.

TheCommissiononLegalEmpowermentforthePoorfoundthat“…fourbillionpeoplearoundtheworldarerobbedofthechancetobettertheirlivesandclimboutofpoverty,becausetheyareexcludedfromtheruleoflaw”(AlbrightanddeSoto,2008).WeknowthatthereisalinkbetweenthestrengthoftheRuleofLawandlevelsofviolence.Thecostofviolence,israrelyprovidedasjustificationforRuleofLawprogramming.Similarly,thespecificeconomicbenefitsofempowermentprogramsarerarelycalculated,letalonecitedasjustificationforgovernmentinterestintheirsupport.Governments(andnon-stateactors),particularlythosethathavefoughttocapturethestate,mayperceivebottom-upRuleofLawprogrammingasunderminingtheircontroloverresourcedistribution,revenuecollectionandotherruleoflaw-relatedleversofpower(Hackmann,2012).Persuadinggovernmentsthatbottom-upRuleofLawprogrammingdrivesgrowthforall,elevatesnormativepressurewhilealsoappealingtorealistself-interest.Increasesinincomeamongthebottom40percentalongsideincreasesinequalityofopportunityhasagreaterpositiveimpactongrowththanthatofotherincomequintiles(Narayanetal.,2013).Inequalitydriveslowergrowthanddiminishedmarketefficiency,toasignificantextentasaresultofdiminishedequalityofopportunityforitsmostproductiveasset–itspeople(Stiglitz,2012).

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Fordevelopment,modelinginformsusthatextremepovertywilllowerto3percentby2030ratherthanbetween6.7and4.7percentifthebottom40percent’sincomeincreases2percentfasterthanacountry’smean(Lakneretal.,2014).Fordevelopmentpractitionersandforgovernments,thesefindingsarecriticaltoourapproachtopolicyplanning,andourselection,designandimplementationofinterventions.

Weknowthatthe‘bottom40’disproportionatelyspendtheirincome,andtherebyincreasethevelocityofmoneyinaneconomycausinganincreasedmultiplierofsecondaryeffects,includingincreasesingovernment’staxrevenue(Kahn,1931;Rivas,2003).Weknowthatgrowth,disproportionatelyexperiencedbythetopquintile,conversely,alsocorrelatestocapitalf