简介：Recurrenteventsdataandgaptimesbetweenrecurrenteventsarefrequentlyencounteredinmanyclinicalandobservationalstudies,andoftenmorethanonetypeofrecurrenteventsisofinterest.Inthispaper,weconsideraproportionalhazardsmodelformultipletyperecurrentgaptimesdatatoassesstheeffectofcovaxiatesonthecensoredeventprocessesofinterest.Anestimatingequationapproachisusedtoobtaintheestimatorsofregressioncoefficientsandbaselinecumulativehazardfunctions.Weexamineasymptoticpropertiesoftheproposedestimators.Finitesamplepropertiesoftheseestimatorsaredemonstratedbysimulations.

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简介：Generalizedcase-cohortdesignhasbeenprovedtobeacost-effectivewaytoenhancetheefficiencyoflargeepidemiologicalcohort.Inthisarticle,weproposeaninferenceprocedureforestimatingtheunknownparametersinCox’sproportionalhazardsmodelingeneralizedcase-cohortdesignandestablishanoptimalsamplesizeallocationtoachievethemaximumpoweratagivenbudget.Thefinitesampleperformanceoftheproposedmethodisevaluatedthroughsimulationstudies.TheproposedmethodisappliedtoarealdatasetfromtheNationalWilm’sTumorStudyGroup.