مرکز منطقه ای اطلاع رساني علوم و فناوري

Abstract :

Between1980andtheearly1990sthevariabilityoflaborearningsgrowthratesacross the prime-ageworkingpopulationfellsignificantly.Thisdeclineandtimingare consistentwithothermacroandmicroobservationsaboutgrowthvariabilitythatare collectivelyreferredtoasthe‘‘GreatModeration.’’Thevariabilityofearningsgrowthis negativelycorrelatedwithageatanypointintime,andtheU.S.workingagepopulation got olderduringthisperiodbecausetheBabyBoomwasaging.However,thedecreasein variabilitywasroughlyuniformacrossallagegroups,sopopulationagingisnotthe sourceoftheoveralldecline.Thevarianceoflogchangesalsodeclinedatmulti-year frequenciesinsuchawayastosuggestthatbothpermanentandtransitorycomponents of earningsshocksbecamemoremoderate.Asimpleidentificationstrategyfor separatingageandcohorteffectsshowsaveryintuitivepatternofpermanentand transitoryshocksoverthelifecycle,andconfirmsthatashiftovertimeinthestochastic process occurredevenaftercontrollingforageeffects