2023
Accounting for expected attrition in the planning of cluster randomized trials for assessing treatment effect heterogeneity
Tong J, Li F, Harhay M, Tong G. Accounting for expected attrition in the planning of cluster randomized trials for assessing treatment effect heterogeneity. BMC Medical Research Methodology 2023, 23: 85. PMID: 37024809, PMCID: PMC10077680, DOI: 10.1186/s12874-023-01887-8.Peer-Reviewed Original ResearchConceptsSample size methodsSample size proceduresSize proceduresTreatment effect heterogeneityHeterogeneous treatment effectsSize methodMissingness ratesSample size formulaSample size estimationMissingness indicatorsEffect heterogeneityReal-world examplesSimulation studyIntracluster correlation coefficientInflation methodSize formulaAverage treatment effectResultsSimulation resultsSample size estimatesSize estimationMissingnessSample sizeClustersEstimationFormula
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
2020
A note on the estimation and inference with quadratic inference functions for correlated outcomes
Yu H, Tong G, Li F. A note on the estimation and inference with quadratic inference functions for correlated outcomes. Communications In Statistics - Simulation And Computation 2020, 51: 6525-6536. PMID: 36568127, PMCID: PMC9782733, DOI: 10.1080/03610918.2020.1805463.Peer-Reviewed Original ResearchQuadratic inference functionsInference functionScore equationsQuadratic inference function approachRegression parametersFinite samplesCombination of estimatorsGeneral settingEquationsCorrelated outcomesSimulation studyEstimatorFunction approachAnalytical insightsPopular methodInferenceSolutionMultiple setsMisspecificationSetFunctionEstimationAlternative solutionNoteParameters