Featured Publications
The required size of cluster randomized trials of nonpharmaceutical interventions in epidemic settings
Sheen J, Haushofer J, Metcalf C, Kennedy‐Shaffer L. The required size of cluster randomized trials of nonpharmaceutical interventions in epidemic settings. Statistics In Medicine 2022, 41: 2466-2482. PMID: 35257398, PMCID: PMC9111156, DOI: 10.1002/sim.9365.Peer-Reviewed Original ResearchConceptsCluster randomized trialEffectiveness of interventionsSample sizeRandomized trialsPlanning such trialsApproximate sample size formulaeReduce transmissionEffect sizeNonpharmaceutical interventionsInfectious disease outbreaksObservational studyInterventionEpidemic settingsSample size methodsAdequate powerSARS-CoV-2 pandemicSARS-CoV-2 transmissionSample size formulaTested individualsSimulated bankTreatment effectsTrialsCommunity transmissionOutbreak settingsSize formulaSample size estimation for stratified individual and cluster randomized trials with binary outcomes
Kennedy‐Shaffer L, Hughes M. Sample size estimation for stratified individual and cluster randomized trials with binary outcomes. Statistics In Medicine 2020, 39: 1489-1513. PMID: 32003492, PMCID: PMC7247053, DOI: 10.1002/sim.8492.Peer-Reviewed Original ResearchConceptsCluster randomized trialIndividual randomized trialsIntracluster correlation coefficientSample size estimationBinary outcomesRandomized trialsSample sizeStratify individualsLogistic regressionSample size reductionProbabilities of eventsContinuous outcomesSize estimationStratified trialCorrelation coefficientOutcomesTrialsEstimationProbability
2021
Power and sample size calculations for cluster randomized trials with binary outcomes when intracluster correlation coefficients vary by treatment arm
Kennedy-Shaffer L, Hughes M. Power and sample size calculations for cluster randomized trials with binary outcomes when intracluster correlation coefficients vary by treatment arm. Clinical Trials 2021, 19: 42-51. PMID: 34879711, PMCID: PMC8883478, DOI: 10.1177/17407745211059845.Peer-Reviewed Original ResearchConceptsWorking correlation structureIntracluster correlation coefficientIntracluster correlation coefficient valuesAsymptotic varianceCorrelation structureClustered binary dataSample size requirementsSample size calculationCluster-level covariatesExchangeable working correlation structureCluster randomized trialModest-sized clustersBinary covariateSize calculationBinary outcomesBinary dataDistribution of cluster sizesFormulaCluster size distributionSize requirementsCovariatesEquationsSample sizeCluster sizeRandomized trials