Sample Size

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  Subject Areas on Research

  • 7 questions to ask when evaluating a noninferiority trial. 
  • 8 steps to a chart audit for quality. 
  • A Bayesian approach on sample size calculation for comparing means. 
  • A Novel Method to Estimate Long-Term Chronological Changes From Fragmented Observations in Disease Progression. 
  • A comparison of hemoglobin measured by co-oximetry and central laboratory during major spine fusion surgery. 
  • A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials. 
  • A genome-wide linkage and association scan reveals novel loci for autism. 
  • A note on sample size calculation based on propensity analysis in nonrandomized trials. 
  • A note on sample size calculation for mean comparisons based on noncentral t-statistics. 
  • A note on sample size determination for bioequivalence studies with high-order crossover designs. 
  • A pilot study of a weight management program with food provision in schizophrenia. 
  • A practical approach for comparing means of two groups without equal variance assumption. 
  • A practical approach for comparing means of two groups without equal variance assumption: H. Wang and S. Chow, Statistics in Medicine 2002; 21:3137-3151. 
  • A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: Rationale and design of the RIVER trial. 
  • A saturated map of common genetic variants associated with human height. 
  • A spline-based algorithm for continuous time-delay estimation using sampled data. 
  • A study design to assess the safety and efficacy of on-pump versus off-pump coronary bypass grafting: the ROOBY trial. 
  • Adaptive Designs for Clinical Trials: Application to Healthcare Epidemiology Research. 
  • Adaptive design in clinical research: issues, opportunities, and recommendations. 
  • Adaptive group sequential test for clinical trials with changing patient population. 
  • Adjusting for misclassification in a stratified biomarker clinical trial. 
  • Adrenal function links to early postnatal growth and blood pressure at age 6 in children born extremely preterm. 
  • Age-related rarefaction in the fractal dimension of retinal vessel. 
  • Alternate analysis strategies for retrospective assessment of outcomes with a male donor-only plasma policy. 
  • An adapted F-test for homogeneity of variability in follow-on biological products. 
  • An evaluation of constrained randomization for the design and analysis of group-randomized trials with binary outcomes. 
  • An evaluation of factors influencing Bayesian learning systems. 
  • An improved method for bivariate meta-analysis when within-study correlations are unknown. 
  • An innovative pay-for-performance (P4P) strategy for improving malaria management in rural Kenya: protocol for a cluster randomized controlled trial. 
  • An observer study methodology for evaluating detection of motion abnormalities in gated myocardial perfusion SPECT. 
  • An overview of variance inflation factors for sample-size calculation. 
  • Analysis of time-to-event data under a two-stage survival adaptive design in clinical trials. 
  • Application of a sequential multiple assignment randomized trial (SMART) design in older patients with chronic lymphocytic leukemia. 
  • Applications of the bayesian prior information to evaluation of equivalence of similar biological medicinal products. 
  • Are linear regression techniques appropriate for analysis when the dependent (outcome) variable is not normally distributed? 
  • Assessing departure from dose linearity under a repeated measures incomplete block design. 
  • Assessing the consistency of traditional Chinese medicine with multiple correlative active components. 
  • Automated liver sampling using a gradient dual-echo Dixon-based technique. 
  • Bayesian hierarchically weighted finite mixture models for samples of distributions. 
  • Bayesian inference in two-phase prevalence studies. 
  • Benefits, challenges and obstacles of adaptive clinical trial designs. 
  • Best (but oft-forgotten) practices: sample size and power calculation for a dietary intervention trial with episodically consumed foods. 
  • Best practices and joint calling of the HumanExome BeadChip: the CHARGE Consortium. 
  • Bias testing, bias correction, and confounder selection using an instrumental variable model. 
  • CYP3A probes can quantitatively predict the in vivo kinetics of other CYP3A substrates and can accurately assess CYP3A induction and inhibition. 
  • Characteristics of clinical trials registered in ClinicalTrials.gov, 2007-2010. 
  • Characteristics of pediatric cardiovascular clinical trials registered on ClinicalTrials.gov. 
  • Cognitive function after major noncardiac surgery, apolipoprotein E4 genotype, and biomarkers of brain injury. 
  • Community-based newborn care in Bangladesh. 
  • Conclusions inconsistent with results with amphetamines and divalproex. 
  • Congenital Heart Surgery Case Mix Across North American Centers and Impact on Performance Assessment. 
  • Connect MDS/AML: design of the myelodysplastic syndromes and acute myeloid leukemia disease registry, a prospective observational cohort study. 
  • Consistency between trials presented at conferences, their subsequent publications and press releases. 
  • Covariate adjustment in heart failure randomized controlled clinical trials: a case analysis of the HF-ACTION trial. 
  • Covariate adjustment in subgroup analyses of randomized clinical trials: A propensity score approach. 
  • Covariate adjustment increased power in randomized controlled trials: an example in traumatic brain injury. 
  • Data monitoring and large apparent treatment effects. 
  • Design and Analysis of Biosimilar Switching Studies. 
  • Design and Implementation of the International Genetics and Translational Research in Transplantation Network. 
  • Design issues in randomized phase II/III trials. 
  • Design of multishell sampling schemes with uniform coverage in diffusion MRI. 
  • Design of the Dialysis Access Consortium (DAC) Aggrenox Prevention Of Access Stenosis Trial. 
  • Design, methodological issues and participation in a multiple sclerosis case-control study. 
  • Determination of an optimal image frame interval for frame-to-frame ultrasound image motion tracking. 
  • Determining Sample Size in Improvement Science Study Designs. 
  • Developing a Real-Time Electroencephalogram-Guided Anesthesia-Management Curriculum for Educating Residents: A Single-Center Randomized Controlled Trial. 
  • Developing a synthetic psychosocial stress measure and harmonizing CVD-risk data: a way forward to GxE meta- and mega-analyses. 
  • Development of Concise Physical Performance Test Batteries in Young Athletes. 
  • Development of a test of physical performance for the nursing home setting. 
  • Direct sampled I/Q beamforming for compact and very low-cost ultrasound imaging. 
  • Doubly-robust estimators of treatment-specific survival distributions in observational studies with stratified sampling. 
  • Eating, Sleeping, Consoling for Neonatal Opioid Withdrawal (ESC-NOW): a Function-Based Assessment and Management Approach study protocol for a multi-center, stepped-wedge randomized controlled trial. 
  • Effect of Discontinuing vs Continuing Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers on Days Alive and Out of the Hospital in Patients Admitted With COVID-19: A Randomized Clinical Trial. 
  • Effect of Smoking Cessation on the Pharmacokinetics and Pharmacodynamics of Clopidogrel after PCI: The Smoking Cessation Paradox Study. 
  • Effect of dropouts on sample size estimates for test on trends across repeated measurements. 
  • Effects of sampling strategy on image quality in noncontact panoramic fluorescence diffuse optical tomography for small animal imaging. 
  • Effects of soft drink consumption on nutrition and health: a systematic review and meta-analysis. 
  • Effects of telerehabilitation on physical function and disability for stroke patients: a randomized, controlled trial. 
  • Efficacy and safety of certolizumab pegol monotherapy every 4 weeks in patients with rheumatoid arthritis failing previous disease-modifying antirheumatic therapy: the FAST4WARD study. 
  • Efficacy of single-dose, multilevel paravertebral nerve blockade for analgesia after thoracoscopic procedures. 
  • Estimating live birth rates after ovulation induction in polycystic ovary syndrome: sample size calculations for the pregnancy in polycystic ovary syndrome trial. 
  • Evaluation of genotype-specific survival using joint analysis of genetic and non-genetic subsamples of longitudinal data. 
  • Evaluations of the sum-score-based and item response theory-based tests of group mean differences under various simulation conditions. 
  • Explicating heterogeneity of complex traits has strong potential for improving GWAS efficiency. 
  • Exploratory analyses of clinical trial data used for health technology assessments: a retrospective evaluation. 
  • Feasibility of clinical detection of cervical dysplasia using angle-resolved low coherence interferometry measurements of depth-resolved nuclear morphology. 
  • Fluvoxamine-controlled release formulation for the treatment of generalized social anxiety disorder. 
  • Fragility Index in Cardiovascular Randomized Controlled Trials. 
  • Frequency estimator for assessing of follow-on biologics. 
  • GRADE guidelines 6. Rating the quality of evidence--imprecision. 
  • Gene-environment interactions in cancer epidemiology: a National Cancer Institute Think Tank report. 
  • Genetic diversity fuels gene discovery for tobacco and alcohol use. 
  • Genomics: Lessons in complexity from yeast. 
  • Good research practices for cost-effectiveness analysis alongside clinical trials: the ISPOR RCT-CEA Task Force report. 
  • Graphical search for two-stage designs for phase II clinical trials. 
  • Group sequential testing for cluster randomized trials with time-to-event endpoint. 
  • Guidelines for STEMI. 
  • HIV quasispecies and resampling. 
  • Have randomized controlled trials of neuroprotective drugs been underpowered? An illustration of three statistical principles. 
  • Hemicraniectomy and durotomy upon deterioration from infarction-related swelling trial: randomized pilot clinical trial. 
  • Homeopathic treatments in psychiatry: a systematic review of randomized placebo-controlled studies. 
  • How few? Bayesian statistics in injury biomechanics. 
  • Hypertension Intervention Nurse Telemedicine Study (HINTS): testing a multifactorial tailored behavioral/educational and a medication management intervention for blood pressure control. 
  • Immunologic escape after prolonged progression-free survival with epidermal growth factor receptor variant III peptide vaccination in patients with newly diagnosed glioblastoma. 
  • Impact of unequal cluster sizes for GEE analyses of stepped wedge cluster randomized trials with binary outcomes. 
  • Importance sampling for the infinite sites model. 
  • In regard to Ghaly et al., IJROBP 2003;55:1288-1293. 
  • In vitro bioequivalence testing. 
  • Individual bioequivalence testing under 2x3 designs. 
  • Inhaled PGE1 in neonates with hypoxemic respiratory failure: two pilot feasibility randomized clinical trials. 
  • Innovative Design and Analysis for PK/PD Biosimilar Bridging Studies with Multiple References. 
  • Interim analysis of binary outcome data in clinical trials: a comparison of five estimators. 
  • Intra-cluster correlations from the CLustered OUtcome Dataset bank to inform the design of longitudinal cluster trials. 
  • Intracluster correlation adjustments to maintain power in cluster trials for binary outcomes. 
  • Is NNT AOK? 
  • Low-molecular-weight heparin to prevent postpartum venous thromboembolism. A pilot randomised placebo-controlled trial. 
  • Low-rank total variation for image super-resolution. 
  • Macroecological patterns of genetic structure and diversity in the aquatic moss Platyhypnidium riparioides. 
  • Management of hypertension and multiple risk factors to enhance cardiovascular health in Singapore: The SingHypertension cluster randomized trial. 
  • Marginal modeling of cluster-period means and intraclass correlations in stepped wedge designs with binary outcomes. 
  • Maximizing ecological and evolutionary insight in bisulfite sequencing data sets. 
  • Maximizing the Yield of Small Samples in Prevention Research: A Review of General Strategies and Best Practices. 
  • Mean shift is a bound optimization. 
  • Medium matters: modeling the impact of solid medium performance on tuberculosis trial sample size requirements. 
  • Meta-analysis of phase II cooperative group trials in metastatic stage IV melanoma to determine progression-free and overall survival benchmarks for future phase II trials. 
  • Methodological challenges in the evaluation of prognostic factors in breast cancer. 
  • Methods of testing feasibility for sequenced treatment alternatives to relieve depression (STAR*D). 
  • Microvolume trace environmental analysis using peak-focusing online solid-phase extraction-nano-liquid chromatography-high-resolution mass spectrometry. 
  • Mixed noninferiority margin and statistical tests in active controlled trials. 
  • Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function. 
  • Non-surgical management of stress urinary incontinence: ambulatory treatments for leakage associated with stress (ATLAS) trial. 
  • Nonparametric Bayes modeling for case control studies with many predictors. 
  • On Enrichment Strategies for Biomarker Stratified Clinical Trials. 
  • On Two-stage Seamless Adaptive Design in Clinical Trials. 
  • On assessing bioequivalence using genomic data with model misspecification. 
  • On classification with incomplete data. 
  • On power and sample size calculation for QT studies with recording replicates at given time point. 
  • On random sample size, ignorability, ancillarity, completeness, separability, and degeneracy: sequential trials, random sample sizes, and missing data. 
  • On sample size calculation based on odds ratio in clinical trials. 
  • On sample size calculation for comparing survival curves under general hypothesis testing. 
  • On sample size calculation in bioequivalence trials. 
  • On sample size estimation and re-estimation adjusting for variability in confirmatory trials. 
  • On sample size requirement for analytical similarity assessment. 
  • On statistical tests for homogeneity of two bivariate zero-inflated Poisson populations. 
  • On the design and the analysis of stratified biomarker trials in the presence of measurement error. 
  • Optimal designs for phase II clinical trials with heterogeneous patient populations. 
  • Optimal two-stage log-rank test for randomized phase II clinical trials. 
  • Overview of registered studies in orthodontics: Evaluation of the ClinicalTrials.gov registry. 
  • Phase II cancer clinical trials for biomarker-guided treatments. 
  • Phase II cancer clinical trials with heterogeneous patient populations. 
  • Phase II clinical trials with time-to-event endpoints: optimal two-stage designs with one-sample log-rank test. 
  • Population genetic structure of Arabidopsis lyrata in Europe. 
  • Power and sample size calculation for microarray studies. 
  • Power and sample size calculations for SNP association studies with censored time-to-event outcomes. 
  • Power and sample size calculations for the Wilcoxon-Mann-Whitney test in the presence of death-censored observations. 
  • Power and sample size requirements for GEE analyses of cluster randomized crossover trials. 
  • Power considerations for generalized estimating equations analyses of four-level cluster randomized trials. 
  • Power considerations for trials of two experimental arms versus a standard active control or placebo. 
  • Power considerations when a continuous outcome variable is dichotomized. 
  • Practical approach to determine sample size for building logistic prediction models using high-throughput data. 
  • Predictors of non-adherence to antiretroviral therapy among HIV infected patients in northern Tanzania. 
  • Probability monitoring procedures for sample size determination. 
  • Proposals of statistical consideration to evaluation of results for a specific region in multi-regional trials--Asian perspective. 
  • Quality of life and long-term outcomes after hospitalization for COVID-19: Protocol for a prospective cohort study (Coalition VII). 
  • Quantification of total T-cell receptor diversity by flow cytometry and spectratyping. 
  • RU486 blocks the anti-inflammatory effects of exercise in a murine model of allergen-induced pulmonary inflammation. 
  • Randomized clinical trial design for assessing noninferiority when superiority is expected. 
  • Randomized phase II clinical trials. 
  • Reconstructing the temporal ordering of biological samples using microarray data. 
  • Recruitment and retention rates in behavioral trials involving patients and a support person: a systematic review. 
  • Reduced length of hospital stay in colorectal surgery after implementation of an enhanced recovery protocol. 
  • Reducing patient eligibility criteria in cancer clinical trials. 
  • Review of Recent Methodological Developments in Group-Randomized Trials: Part 1-Design. 
  • Risk adjustment of ischemic stroke outcomes for comparing hospital performance: a statement for healthcare professionals from the American Heart Association/American Stroke Association. 
  • Robust statistical inference for matched win statistics. 
  • SAHIT Investigators--on the outcome of some subarachnoid hemorrhage clinical trials. 
  • SMARTer discontinuation trial designs for developing an adaptive treatment strategy. 
  • Salvage Radiation Therapy Dose Response for Biochemical Failure of Prostate Cancer After Prostatectomy-A Multi-Institutional Observational Study. 
  • Sample Size Considerations in Prevention Research Applications of Multilevel Modeling and Structural Equation Modeling. 
  • Sample size and interim analysis issues for dose selection. 
  • Sample size and power calculation for molecular biology studies. 
  • Sample size calculation for cluster randomization trials with a time-to-event endpoint. 
  • Sample size calculation for clustered survival data under subunit randomization. 
  • Sample size calculation for multiple testing in microarray data analysis. 
  • Sample size calculation for simulation-based multiple-testing procedures. 
  • Sample size calculation for studies with grouped survival data. 
  • Sample size calculation for the weighted rank statistics with paired survival data. 
  • Sample size calculation for weighted rank tests comparing survival distributions under cluster randomization: a simulation method. 
  • Sample size calculation in bioequivalence trials. 
  • Sample size calculations for clustered binary data. 
  • Sample size calculations for evaluating a diagnostic test when the gold standard is missing at random. 
  • Sample size calculations for evaluating a diagnostic test when the gold standard is missing at random. 
  • Sample size calculations for the design of cluster randomized trials: A summary of methodology. 
  • Sample size computation for two-sample noninferiority log-rank test. 
  • Sample size considerations of prediction-validation methods in high-dimensional data for survival outcomes. 
  • Sample size determination based on rank tests in clinical trials. 
  • Sample size determination for GEE analyses of stepped wedge cluster randomized trials. 
  • Sample size determination for comparing several survival curves with unequal allocations. 
  • Sample size determination for jointly testing a cause-specific hazard and the all-cause hazard in the presence of competing risks. 
  • Sample size estimation based on event data for a two-stage survival adaptive trial with different durations. 
  • Sample size estimation for GEE method for comparing slopes in repeated measurements data. 
  • Sample size estimation of multiregional clinical trials with heterogeneous variability across regions. 
  • Sample size for FDR-control in microarray data analysis. 
  • Sample size for a two-group comparison of repeated binary measurements using GEE. 
  • Sample size for biomarker studies: more subjects or more measurements per subject? 
  • Sample size for comparing correlated concordance rates. 
  • Sample size re-estimation in clinical trials. 
  • Sample size requirement in analytical studies for similarity assessment. 
  • Sample size requirements for detecting treatment effect heterogeneity in cluster randomized trials. 
  • Scientific factors and current issues in biosimilar studies. 
  • Seamless Phase IIa/IIb and enhanced dose-finding adaptive design. 
  • Semiparametric tests for identifying differentially methylated loci with case-control designs using Illumina arrays. 
  • Sensible guidelines for the conduct of large randomized trials. 
  • Sequenced treatment alternatives to relieve depression (STAR*D): rationale and design. 
  • Sequencing of 53,831 diverse genomes from the NHLBI TOPMed Program. 
  • Sequential Multiple Assignment Randomized Trial (SMART) to identify optimal sequences of telemedicine interventions for improving initiation of insulin therapy: A simulation study. 
  • Single-voxel 1H PRESS at 4.0 T: precision and variability of measurements in anterior cingulate and hippocampus. 
  • Staphylococcus aureus bacteremia after median sternotomy: clinical utility of blood culture results in the identification of postoperative mediastinitis. 
  • Statistical analysis for two-stage seamless design with different study endpoints. 
  • Statistical assessment of QT/QTc prolongation based on maximum of correlated normal random variables. 
  • Statistical considerations for the design and analysis of Phase III clinical trials in prostate cancer. 
  • Statistical inference for clinical trials with binary responses when there is a shift in patient population. 
  • Statistical issues for design and analysis of single-arm multi-stage phase II cancer clinical trials. 
  • Statistical methods in translational medicine. 
  • Statistical quality control process for traditional Chinese medicine. 
  • Steroids for restenosis: strike three! 
  • Stochastic variation in network epidemic models: implications for the design of community level HIV prevention trials. 
  • Stratified Fisher's exact test and its sample size calculation. 
  • Survey methodology for the uninitiated. 
  • Telemedicine cardiovascular risk reduction in veterans. 
  • Testing homogeneity of intra-run variance parameters in immunoassay. 
  • Testing small study effects in multivariate meta-analysis. 
  • Tests for inter-subject and total variabilities under crossover designs. 
  • The American College of Rheumatology response criteria for systemic lupus erythematosus clinical trials: measures of overall disease activity. 
  • The CSL112-2001 trial: Safety and tolerability of multiple doses of CSL112 (apolipoprotein A-I [human]), an intravenous formulation of plasma-derived apolipoprotein A-I, among subjects with moderate renal impairment after acute myocardial infarction. 
  • The Complexity of Conducting a Multicenter Clinical Trial: Taking It to the Next Level Stipulated by the Federal Agencies. 
  • The NeuroAiD II (MLC901) in vascular cognitive impairment study (NEURITES). 
  • The Self-Management of OsteoArthritis in Veterans (SeMOA) Study: design and methodology. 
  • The Vitamin C, Thiamine and Steroids in Sepsis (VICTAS) Protocol: a prospective, multi-center, double-blind, adaptive sample size, randomized, placebo-controlled, clinical trial. 
  • The accuracy of statistical estimates in genetic studies of aging can be significantly improved. 
  • The association of anti-platelet factor 4/heparin antibodies with early and delayed thromboembolism after cardiac surgery. 
  • The bootstrap procedure in individual bioequivalence. 
  • The clinician as investigator: participating in clinical trials in the practice setting: Appendix 1: fundamentals of study design. 
  • The clinician as investigator: participating in clinical trials in the practice setting: Appendix 2: statistical concepts in study design and analysis. 
  • The future of clinical trials in secondary prevention after acute coronary syndromes. 
  • The genetic architecture of type 2 diabetes. 
  • The normality assumption on between-study random effects was questionable in a considerable number of Cochrane meta-analyses. 
  • The physiological ecology of the supratidal amphipod Talorchestia longicornis. 
  • The quick inventory of depressive symptomatology (clinician and self-report versions) in patients with bipolar disorder. 
  • The use of 95% CI or 90% CI for drug product development - a controversial issue? 
  • The use of Bayesian hierarchical models for adaptive randomization in biomarker-driven phase II studies. 
  • The use of single-nucleotide polymorphism maps in pharmacogenomics. 
  • Ticagrelor in Peripheral Artery Disease Endovascular Revascularization (TI-PAD): Challenges in clinical trial execution. 
  • Trial to Incentivise Adherence for Diabetes (TRIAD): study protocol for a randomised controlled trial. 
  • Two Questions About the Design of Cluster Randomized Trials: A Tutorial. 
  • Two weights make a wrong: Cluster randomized trials with variable cluster sizes and heterogeneous treatment effects. 
  • Uncertainty in allometric exponent estimation: a case study in scaling metabolic rate with body mass. 
  • Update to the Vitamin C, Thiamine and Steroids in Sepsis (VICTAS) protocol: statistical analysis plan for a prospective, multicenter, double-blind, adaptive sample size, randomized, placebo-controlled, clinical trial. 
  • Use of a rapid electronic survey methodology to estimate blood donors' potential exposure to emerging infectious diseases: Application of a statistically representative sampling methodology to assess risk in US blood centers. 
  • Use of larger versus smaller drug-safety databases before regulatory approval: the trade-offs. 
  • Using pilot data to size a two-arm randomized trial to find a nearly optimal personalized treatment strategy. 
  • Variant-specific inflation factors for assessing population stratification at the phenotypic variance level. 
  • Variation of serum hyaluronan with activity in individuals with knee osteoarthritis. 
  • What Constitutes a Well-Designed Pilot Study? 
  • What can we learn from a decade of database audits? The Duke Clinical Research Institute experience, 1997--2006. 
  • Where the rubber meets the road in pharmacogenetics: assessment of gene-environment interactions. 
  • Working With Statisticians in Clinical Research. 
  • gsSKAT: Rapid gene set analysis and multiple testing correction for rare-variant association studies using weighted linear kernels. 
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  Keywords of People

  • Badea, Cristian Tudorel, Professor in Radiology, Biomedical Engineering
  • Halabi, Susan, Professor of Biostatistics & Bioinformatics, Biostatistics & Bioinformatics
  • Laskowitz, Daniel Todd, Professor of Neurology, Duke Science & Society
  • McLendon, Roger Edwin, Professor of Pathology, Pathology
  • O'Connor, Christopher Michael, Adjunct Professor in the Department of Medicine, Medicine, Clinical Pharmacology
  • Olsen, Maren Karine, Professor of Biostatistics & Bioinformatics, Biostatistics & Bioinformatics
  • Sampson, John Howard, Robert H., M.D. and Gloria Wilkins Professor of Neurosurgery, in the School of Medicine, Biomedical Engineering