2022
Clustered restricted mean survival time regression
Chen X, Harhay MO, Li F. Clustered restricted mean survival time regression. Biometrical Journal 2022, 65: e2200002. PMID: 35593026, DOI: 10.1002/bimj.202200002.Peer-Reviewed Original ResearchConceptsSandwich variance estimatorVariance estimatorValid inferencesRegression coefficient estimatesSmall sample scenariosContinuous functionsCluster correlationEffects of covariatesEstimatorHazard functionTarget parametersCoefficient estimatesMultilevel observational studyTime regressionRegression coefficientsInferenceEvent outcomesEquationsRegression modelsModelCritical assumptionsSufficient numberSimulationsFunctionAssumption
2021
Sample size estimation for modified Poisson analysis of cluster randomized trials with a binary outcome
Li F, Tong G. Sample size estimation for modified Poisson analysis of cluster randomized trials with a binary outcome. Statistical Methods In Medical Research 2021, 30: 1288-1305. PMID: 33826454, PMCID: PMC9132618, DOI: 10.1177/0962280221990415.Peer-Reviewed Original ResearchConceptsSample size formulaExchangeable working correlationExtensive Monte Carlo simulation studySize formulaMonte Carlo simulation studyFinite sample correctionMarginal relative riskCorresponding sample size formulaeSandwich variance estimatorVariable cluster sizesNumber of clustersAsymptotic efficiencySandwich varianceCluster size variabilityRobust sandwich varianceSample size estimationVariance estimatorAnalytical derivationSimulation studyCluster sizePoisson modelCoefficient estimatesFormulaCorrelation coefficient estimatesBinary outcomes