2021
Power considerations for generalized estimating equations analyses of four‐level cluster randomized trials
Wang X, Turner EL, Preisser JS, Li F. Power considerations for generalized estimating equations analyses of four‐level cluster randomized trials. Biometrical Journal 2021, 64: 663-680. PMID: 34897793, PMCID: PMC9574475, DOI: 10.1002/bimj.202100081.Peer-Reviewed Original ResearchConceptsCorrelation structureClosed-form sample size formulaModel-based varianceTrue correlation structureSandwich variance estimatorSandwich varianceSample size formulaVariance functionVariance estimatorEmpirical powerCorrelation parametersCorrelation matrixEstimating EquationsSize formulaEquationsArbitrary linkPower considerationsSame clusterPower calculationEstimatorSample sizeEquation analysisClustersFormula
2019
Design and analysis considerations for cohort stepped wedge cluster randomized trials with a decay correlation structure
Li F. Design and analysis considerations for cohort stepped wedge cluster randomized trials with a decay correlation structure. Statistics In Medicine 2019, 39: 438-455. PMID: 31797438, PMCID: PMC7027591, DOI: 10.1002/sim.8415.Peer-Reviewed Original ResearchConceptsQuasi-least squaresCorrelation structureAdditional correlation parameterCluster correlation structureCorrelation parametersSample size proceduresPeriod correlationMultiple outcome measurementsSandwich varianceCorrelation decayPower proceduresSize proceduresEmpirical powerSimulation studySame clusterTrial exampleSquaresAnalysis considerationsWedge designParametersSample sizeContinuous outcomesClusters