sample size

Summary

Summary: The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups. (From Wassertheil-Smoller, Biostatistics and Epidemiology, 1990, p95)

Top Publications

  1. ncbi The kappa statistic in reliability studies: use, interpretation, and sample size requirements
    Julius Sim
    Primary Care Sciences Research Centre, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
    Phys Ther 85:257-68. 2005
  2. ncbi Power failure: why small sample size undermines the reliability of neuroscience
    Katherine S Button
    School of Experimental Psychology, University of Bristol, UK
    Nat Rev Neurosci 14:365-76. 2013
  3. ncbi Reported methodologic quality and discrepancies between large and small randomized trials in meta-analyses
    L L Kjaergard
    Cochrane Hepato Biliary Group, Copenhagen Trial Unit, Center for Clinical Intervention Research, Copenhagen University Hospital, H S Rigshospitalet, DK 2100 Copenhagen, Denmark
    Ann Intern Med 135:982-9. 2001
  4. ncbi The performance of tests of publication bias and other sample size effects in systematic reviews of diagnostic test accuracy was assessed
    Jonathan J Deeks
    Screening and Test Evaluation Program, School of Public Health, University of Sydney, Sydney, New South Wales 2006, Australia
    J Clin Epidemiol 58:882-93. 2005
  5. ncbi Trial sequential analysis may establish when firm evidence is reached in cumulative meta-analysis
    Jørn Wetterslev
    Copenhagen Trial Unit, Centre for Clinical Intervention Research, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, Copenhagen, Denmark
    J Clin Epidemiol 61:64-75. 2008
  6. pmc Why most published research findings are false
    John P A Ioannidis
    Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece
    PLoS Med 2:e124. 2005
  7. ncbi What is an adequate sample size? Operationalising data saturation for theory-based interview studies
    Jill J Francis
    Health Services Research Unit, University of Aberdeen, Aberdeen, UK
    Psychol Health 25:1229-45. 2010
  8. ncbi A global test for groups of genes: testing association with a clinical outcome
    Jelle J Goeman
    Department of Medical Statistics, Leiden University Medical Center, P O Box 9604, 2300 RC Leiden, The Netherlands
    Bioinformatics 20:93-9. 2004
  9. ncbi Genetic Power Calculator: design of linkage and association genetic mapping studies of complex traits
    S Purcell
    Social, Genetics and Developmental Psychiatry Research Centre, Institute of Psychiatry, King s College London, De Crespigny Park, UK
    Bioinformatics 19:149-50. 2003
  10. pmc Designing genome-wide association studies: sample size, power, imputation, and the choice of genotyping chip
    Chris C A Spencer
    Department of Statistics, University of Oxford, Oxford, United Kingdom
    PLoS Genet 5:e1000477. 2009

Detail Information

Publications387 found, 100 shown here

  1. ncbi The kappa statistic in reliability studies: use, interpretation, and sample size requirements
    Julius Sim
    Primary Care Sciences Research Centre, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
    Phys Ther 85:257-68. 2005
    ..This article examines and illustrates the use and interpretation of the kappa statistic in musculoskeletal research...
  2. ncbi Power failure: why small sample size undermines the reliability of neuroscience
    Katherine S Button
    School of Experimental Psychology, University of Bristol, UK
    Nat Rev Neurosci 14:365-76. 2013
    ..Improving reproducibility in neuroscience is a key priority and requires attention to well-established but often ignored methodological principles...
  3. ncbi Reported methodologic quality and discrepancies between large and small randomized trials in meta-analyses
    L L Kjaergard
    Cochrane Hepato Biliary Group, Copenhagen Trial Unit, Center for Clinical Intervention Research, Copenhagen University Hospital, H S Rigshospitalet, DK 2100 Copenhagen, Denmark
    Ann Intern Med 135:982-9. 2001
    ..To explore whether reported methodologic quality affects estimated intervention effects in randomized trials and contributes to discrepancies between the results of large randomized trials and small randomized trials in meta-analyses...
  4. ncbi The performance of tests of publication bias and other sample size effects in systematic reviews of diagnostic test accuracy was assessed
    Jonathan J Deeks
    Screening and Test Evaluation Program, School of Public Health, University of Sydney, Sydney, New South Wales 2006, Australia
    J Clin Epidemiol 58:882-93. 2005
    Publication bias and other sample size effects are issues for meta-analyses of test accuracy, as for randomized trials...
  5. ncbi Trial sequential analysis may establish when firm evidence is reached in cumulative meta-analysis
    Jørn Wetterslev
    Copenhagen Trial Unit, Centre for Clinical Intervention Research, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, Copenhagen, Denmark
    J Clin Epidemiol 61:64-75. 2008
    ..Information size in a meta-analysis should at least equal the sample size of an adequately powered trial...
  6. pmc Why most published research findings are false
    John P A Ioannidis
    Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece
    PLoS Med 2:e124. 2005
    ..In this essay, I discuss the implications of these problems for the conduct and interpretation of research...
  7. ncbi What is an adequate sample size? Operationalising data saturation for theory-based interview studies
    Jill J Francis
    Health Services Research Unit, University of Aberdeen, Aberdeen, UK
    Psychol Health 25:1229-45. 2010
    In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this...
  8. ncbi A global test for groups of genes: testing association with a clinical outcome
    Jelle J Goeman
    Department of Medical Statistics, Leiden University Medical Center, P O Box 9604, 2300 RC Leiden, The Netherlands
    Bioinformatics 20:93-9. 2004
    ..Groups of genes may be any size from a single gene to all genes on the chip (e.g. known pathways, specific areas of the genome or clusters from a cluster analysis)...
  9. ncbi Genetic Power Calculator: design of linkage and association genetic mapping studies of complex traits
    S Purcell
    Social, Genetics and Developmental Psychiatry Research Centre, Institute of Psychiatry, King s College London, De Crespigny Park, UK
    Bioinformatics 19:149-50. 2003
    ..A website for performing power calculations for the design of linkage and association genetic mapping studies of complex traits...
  10. pmc Designing genome-wide association studies: sample size, power, imputation, and the choice of genotyping chip
    Chris C A Spencer
    Department of Statistics, University of Oxford, Oxford, United Kingdom
    PLoS Genet 5:e1000477. 2009
    ..comparing different chips is using a measure of coverage, but this fails to properly account for the effects of sample size, the genetic model of the disease, and linkage disequilibrium between SNPs...
  11. ncbi Considerations in determining sample size for pilot studies
    Melody A Hertzog
    College of Nursing, University of Nebraska Medical Center, Lincoln Division, 1230 O Street, Suite 131, P O Box 880220, Lincoln, NE 68588 0220, USA
    Res Nurs Health 31:180-91. 2008
    ..illustrates how confidence intervals constructed around a desired or anticipated value can help determine the sample size needed...
  12. ncbi Sample size for cluster randomized trials: effect of coefficient of variation of cluster size and analysis method
    Sandra M Eldridge
    Centre for Health Sciences, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
    Int J Epidemiol 35:1292-300. 2006
    ..In many of these trials, cluster sizes are unequal. This can affect trial power, but standard sample size formulae for these trials ignore this...
  13. pmc Effects of sample size on robustness and prediction accuracy of a prognostic gene signature
    Seon Young Kim
    Medical Genomics Research Center, KRIBB, Yuseong Gu, Daejeon, Republic of Korea
    BMC Bioinformatics 10:147. 2009
    ..One recent study suggested that thousands of samples are needed to generate a robust prognostic gene signature...
  14. ncbi Sample size estimation: how many individuals should be studied?
    John Eng
    Department of Radiology and Radiological Science, Johns Hopkins University, 600 N Wolfe St, Central Radiology Viewing Area, Rm 117, Baltimore, MD 21287, USA
    Radiology 227:309-13. 2003
    The number of individuals to include in a research study, the sample size of the study, is an important consideration in the design of many clinical studies...
  15. ncbi Trial sequential analysis reveals insufficient information size and potentially false positive results in many meta-analyses
    Jesper Brok
    Copenhagen Trial Unit, Centre for Clinical Intervention Research, The Cochrane Hepato Biliary Group, Dept 3344, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK 2100 Copenhagen, Denmark
    J Clin Epidemiol 61:763-9. 2008
    ..Meta-analyses not reaching information size are analyzed with trial sequential monitoring boundaries analogous to interim monitoring boundaries in a single trial...
  16. pmc Strategies for increasing recruitment to randomised controlled trials: systematic review
    Patrina H Y Caldwell
    Centre for Kidney Research, The Children s Hospital at Westmead, New South Wales, Australia
    PLoS Med 7:e1000368. 2010
    ..The aim of our study was to evaluate the relative effectiveness of recruitment strategies for participation in RCTs...
  17. pmc Treatment allocation by minimisation
    Douglas G Altman
    Cancer Research UK Medical Statistics Group, Centre for Statistics in Medicine, Oxford OX3 7LF
    BMJ 330:843. 2005
  18. ncbi A comparison of meta-analysis methods for detecting differentially expressed genes in microarray experiments
    Fangxin Hong
    Department of Biostatistics, Division of Information Sciences, City of Hope National Medical Center, Beckman Research Institute, 1500 Duarte Rd, Duarte, CA 91010, USA
    Bioinformatics 24:374-82. 2008
    ..While these methods address the question from different angles, it is not clear how they compare with each other...
  19. pmc The number of patients and events required to limit the risk of overestimation of intervention effects in meta-analysis--a simulation study
    Kristian Thorlund
    Department of Clinical Epidemiology and Biostatistics, McMaster University, Ontario, Canada
    PLoS ONE 6:e25491. 2011
    ..It has been suggested that surpassing the optimal information size (i.e., the required meta-analysis sample size) provides sufficient protection against overestimation due to random error, but this claim has not yet been ..
  20. ncbi Evidence-based guidelines for determination of sample size and interpretation of the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30
    Kim Cocks
    Clinical Trials Research Unit, University of Leeds, United Kingdom, LS2 9JT
    J Clin Oncol 29:89-96. 2011
    ....
  21. pmc Diffuse myocardial fibrosis evaluation using cardiac magnetic resonance T1 mapping: sample size considerations for clinical trials
    Songtao Liu
    Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
    J Cardiovasc Magn Reson 14:90. 2012
    ..The aim of this study is to determine the reproducibility and sample size of CMR fibrosis measurements that would be applicable in clinical trials.
  22. pmc Sample size considerations for one-to-one animal transmission studies of the influenza A viruses
    Hiroshi Nishiura
    School of Public Health, The University of Hong Kong, Hong Kong SAR, China
    PLoS ONE 8:e55358. 2013
    ..The analyses are illustrated on transmission studies of influenza A viruses in the ferret model...
  23. pmc Gray matter in first-episode schizophrenia before and after antipsychotic drug treatment. Anatomical likelihood estimation meta-analyses with sample size weighting
    Meikei Leung
    Department of Psychiatry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
    Schizophr Bull 37:199-211. 2011
    ....
  24. ncbi Sample size calculations: basic principles and common pitfalls
    Marlies Noordzij
    ERA EDTA Registry, Department of Medical Informatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
    Nephrol Dial Transplant 25:1388-93. 2010
    One of the most common requests that statisticians get from investigators are sample size calculations or sample size justifications...
  25. pmc Effect of training-sample size and classification difficulty on the accuracy of genomic predictors
    Vlad Popovici
    Bioinformatics Core Facility, Swiss Institute of Bioinformatics, Genopode Building, Quartier Sorge, Lausanne CH 1015, Switzerland
    Breast Cancer Res 12:R5. 2010
    ....
  26. pmc Required sample size to detect the mediated effect
    Matthew S Fritz
    Department of Psychology, Arizona State University, Box 871104, Tempe, AZ 85287 1104, USA
    Psychol Sci 18:233-9. 2007
    ....
  27. ncbi Does feature selection improve classification accuracy? Impact of sample size and feature selection on classification using anatomical magnetic resonance images
    Carlton Chu
    Section on Functional Imaging Methods, Laboratory of Brain and Cognition, NIMH, NIH, Bethesda, USA
    Neuroimage 60:59-70. 2012
    ..In general, larger sample sizes yielded higher accuracies with less advantage obtained by using knowledge from the existing literature...
  28. ncbi Assessing the probability that a positive report is false: an approach for molecular epidemiology studies
    Sholom Wacholder
    Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 7244, USA
    J Natl Cancer Inst 96:434-42. 2004
    ..An FPRP-based criterion for deciding whether to call a finding noteworthy formalizes the process already used informally by investigators--that is, tempering enthusiasm for remarkable study findings with considerations of plausibility...
  29. ncbi Sample size calculations in randomised trials: mandatory and mystical
    Kenneth F Schulz
    Family Health International, PO Box 13950, Research Triangle Park, NC 27709, USA
    Lancet 365:1348-53. 2005
    ..Furthermore, these judgments greatly affect sample size calculations...
  30. ncbi Validation and updating of predictive logistic regression models: a study on sample size and shrinkage
    Ewout W Steyerberg
    Center for Clinical Decision Sciences, Department of Public Health, Erasmus Medical Center, Rotterdam, The Netherlands
    Stat Med 23:2567-86. 2004
    ..Parsimonious updating methods were found preferable to more extensive model revisions, which should only be attempted with relatively large validation samples in combination with shrinkage...
  31. pmc Undue reliance on I(2) in assessing heterogeneity may mislead
    Gerta Rucker
    Institute of Medical Biometry and Medical Informatics, University Medical Center Freiburg, Germany
    BMC Med Res Methodol 8:79. 2008
    ..The heterogeneity statistic I(2), interpreted as the percentage of variability due to heterogeneity between studies rather than sampling error, depends on precision, that is, the size of the studies included...
  32. pmc Reporting of sample size calculation in randomised controlled trials: review
    Pierre Charles
    INSERM, U738, Paris, France
    BMJ 338:b1732. 2009
    To assess quality of reporting of sample size calculation, ascertain accuracy of calculations, and determine the relevance of assumptions made when calculating sample size in randomised controlled trials.
  33. ncbi A simple sample size formula for analysis of covariance in randomized clinical trials
    George F Borm
    Department of Epidemiology and Biostatistics, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21, PO Box 9101, NL 6500 HB Nijmegen, The Netherlands
    J Clin Epidemiol 60:1234-8. 2007
    Randomized clinical trials that compare two treatments on a continuous outcome can be analyzed using analysis of covariance (ANCOVA) or a t-test approach. We present a method for the sample size calculation when ANCOVA is used.
  34. ncbi Sample size and optimal design for logistic regression with binary interaction
    Eugene Demidenko
    Dartmouth Medical School, Hanover, NH 03755, U S A
    Stat Med 27:36-46. 2008
    There is no consensus on what test to use as the basis for sample size determination and power analysis. Some authors advocate the Wald test and some the likelihood-ratio test...
  35. ncbi Determinants of the intracluster correlation coefficient in cluster randomized trials: the case of implementation research
    Marion K Campbell
    Health Services Research Unit, University of Aberdeen, Foresterhill, UK
    Clin Trials 2:99-107. 2005
    ..In conclusion, accurate estimates of ICCs are essential for sample size calculations for cluster randomized trials of professional behaviour change interventions...
  36. pmc Sample size calculations for cluster randomised controlled trials with a fixed number of clusters
    Karla Hemming
    Department of Public Health, Epidemiology and Biostatistics, University of Birmingham, UK
    BMC Med Res Methodol 11:102. 2011
    ..the number of clusters are fixed in advance, but where it is possible to increase the number of individuals within each cluster, as is frequently the case in health service evaluation, sample size formulae have been less well studied.
  37. ncbi Sample size calculation should be performed for design accuracy in diagnostic test studies
    Antoine Flahault
    Unité de biostatistique et d Informatique médicale, Hopital Tenon, Paris, France
    J Clin Epidemiol 58:859-62. 2005
    ..Our objective was to provide tables for sample size determination in this context.
  38. pmc Pitfalls of and controversies in cluster randomization trials
    Allan Donner
    Department of Epidemiology and Biostatistics, University of Western Ontario, London, Canada
    Am J Public Health 94:416-22. 2004
    ..We discuss several topics related to these issues, with emphasis on the choices that must be made in the planning stages of a trial and on some potential pitfalls to be avoided...
  39. pmc Variance estimation, design effects, and sample size calculations for respondent-driven sampling
    Matthew J Salganik
    Department of Sociology, 1180 Amsterdam Avenue, New York, NY 10027, USA
    J Urban Health 83:i98-112. 2006
    ..We conclude with practical advice about the power calculations that are needed to determine the appropriate sample size for a study using respondent-driven sampling...
  40. ncbi Penalized Cox regression analysis in the high-dimensional and low-sample size settings, with applications to microarray gene expression data
    Jiang Gui
    Department of Statistics, University of California Davis, CA 95616, USA
    Bioinformatics 21:3001-8. 2005
    ..It would be desirable to have models with good prediction accuracy and parsimony property...
  41. pmc An introduction to power and sample size estimation
    S R Jones
    North Manchester Hospital, Manchester, UK
    Emerg Med J 20:453-8. 2003
    The importance of power and sample size estimation for study design and analysis.
  42. ncbi Sample size calculator for cluster randomized trials
    Marion K Campbell
    Health Services Research Unit, University of Aberdeen, Polwarth Building Foresterhill, Aberdeen, Scotland AB25 2ZD UK
    Comput Biol Med 34:113-25. 2004
    ..A sample size calculator is presented for calculating appropriate sample sizes for cluster trials, whilst allowing the ..
  43. ncbi A simple sample size formula for analysis of covariance in cluster randomized trials
    Steven Teerenstra
    Department of Epidemiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    Stat Med 31:2169-78. 2012
    For cluster randomized trials with a continuous outcome, the sample size is often calculated as if an analysis of the outcomes at the end of the treatment period (follow-up scores) would be performed...
  44. ncbi Intraclass correlation coefficients for cluster randomized trials in primary care: data from the MRC Trial of the Assessment and Management of Older People in the Community
    Liam Smeeth
    Centre for Ageing and Public Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
    Control Clin Trials 23:409-21. 2002
    ....
  45. ncbi Covariate adjustment in randomized controlled trials with dichotomous outcomes increases statistical power and reduces sample size requirements
    Adrian V Hernandez
    Center for Clinical Decision Sciences, Department of Public Health, Erasmus Medical Center, P O Box 1738, Rotterdam 3000 DR, The Netherlands
    J Clin Epidemiol 57:454-60. 2004
    ..We studied type I error, power, and potential reduction in sample size with several covariate adjustment strategies.
  46. ncbi Estimating allelic richness: effects of sample size and bottlenecks
    P L Leberg
    Department of Biology, University of Louisiana, Lafayette, LA 70504, USA
    Mol Ecol 11:2445-9. 2002
    ..allelic richness (A) among populations, investigators often fail to correct estimates of A for differences in sample size. Methods that standardize A on the basis of the size of the smallest number of samples in a comparison are ..
  47. ncbi Estimating sample size in functional MRI (fMRI) neuroimaging studies: statistical power analyses
    John E Desmond
    Department of Radiology, Lucas MRS Center, MC 5488, Stanford University, Stanford, CA 94305 5488, USA
    J Neurosci Methods 118:115-28. 2002
    ..At more realistic thresholds, that approach those used after correcting for multiple comparisons, the number of subjects doubled to maintain this level of power...
  48. ncbi Adaptive increase in sample size when interim results are promising: a practical guide with examples
    Cyrus R Mehta
    Cytel Corporation, 675 Massachusetts Avenue, Cambridge, MA 02139, USA
    Stat Med 30:3267-84. 2011
    This paper discusses the benefits and limitations of adaptive sample size re-estimation for phase 3 confirmatory clinical trials. Comparisons are made with more traditional fixed sample and group sequential designs...
  49. ncbi Sample size determination for logistic regression revisited
    Eugene Demidenko
    Dartmouth Medical School, Hanover, NH 03755, USA
    Stat Med 26:3385-97. 2007
    There is no consensus on the approach to compute the power and sample size with logistic regression...
  50. pmc Assessing respondent-driven sampling
    Sharad Goel
    Microeconomics and Social Systems, Yahoo Research, 111 West 40th Street, New York, NY 10018, USA
    Proc Natl Acad Sci U S A 107:6743-7. 2010
    ..Given the consistency of our results across networks and our generous sampling conditions, we conclude that RDS as currently practiced may not be suitable for key aspects of public health surveillance where it is now extensively applied...
  51. ncbi Sample size requirements for association studies of gene-gene interaction
    W James Gauderman
    Department of Preventive Medicine, School of Medicine, University of Southern California, 1540 Alcazar Street, Suite 220, Los Angeles, CA 90089, USA
    Am J Epidemiol 155:478-84. 2002
    ..In this paper, the author investigates sample size requirements for studies of G x G interaction, focusing on four study designs: the matched-case-control design, ..
  52. ncbi Design issues of randomized phase II trials and a proposal for phase II screening trials
    Lawrence V Rubinstein
    Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda, MD, USA
    J Clin Oncol 23:7199-206. 2005
    ..error rates (beta or type II error), so that the targeted treatment benefit may be appropriate while the sample size remains restricted...
  53. ncbi Caution regarding the use of pilot studies to guide power calculations for study proposals
    Helena Chmura Kraemer
    Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, Calif 94305, USA
    Arch Gen Psychiatry 63:484-9. 2006
    ..The argument herein is not meant to discourage clinical researchers from performing pilot studies (or review committees from requiring them) but simply to caution against their use for the objective of guiding power calculations...
  54. ncbi Optimal sample sizes for phase II clinical trials and pilot studies
    Nigel Stallard
    Warwick Medical School, University of Warwick, UK
    Stat Med 31:1031-42. 2012
    Methodology for sample size calculation for phase III clinical trials is well established and widely used...
  55. pmc Sample size determination
    Ralph B Dell
    Department of Pediatrics, College of Physicans and Surgeons, Columbia University, New York, NY, USA
    ILAR J 43:207-13. 2002
    ..the number of animals to be used can best be estimated from previous experience and when a simple power and sample size calculation should be performed...
  56. ncbi Minimizing sample size when using exploratory factor analysis for measurement
    Kathryn G Sapnas
    University of Miami, Jackson Memorial Hospital Ryder Trauma Center, Miami, FL, USA
    J Nurs Meas 10:135-54. 2002
    Traditional protocol for the determination of an adequate sample size is power analysis. Such a protocol is not useful when the primary hypothesis focuses on psychometric measurement properties...
  57. ncbi Additive partitioning of rarefaction curves and species-area relationships: unifying alpha-, beta- and gamma-diversity with sample size and habitat area
    Thomas O Crist
    Department of Zoology and Ecology Program, Miami University, Oxford, OH 45056, USA
    Ecol Lett 9:923-32. 2006
    ..Additive partitions can also be applied to species-area relationships to determine the relative contributions of factors influencing the beta-diversity among habitat fragments...
  58. ncbi Apparently conclusive meta-analyses may be inconclusive--Trial sequential analysis adjustment of random error risk due to repetitive testing of accumulating data in apparently conclusive neonatal meta-analyses
    Jesper Brok
    The Copenhagen Trial Unit, Center for Clinical Intervention Research, Department 3344, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
    Int J Epidemiol 38:287-98. 2009
    ..This is analogous to sequential monitoring boundaries in a single trial...
  59. ncbi Design and analysis of clinical trials with clustering effects due to treatment
    Chris Roberts
    Biostatistics Group, Division of Epidemiology and Health Sciences, University of Manchester, UK
    Clin Trials 2:152-62. 2005
    ..The implications of differential clustering effects for sample size and power are addressed...
  60. ncbi Confirmatory seamless phase II/III clinical trials with hypotheses selection at interim: general concepts
    Frank Bretz
    Novartis Pharma AG, Lichtstrasse 35, 4002 Basel, Switzerland
    Biom J 48:623-34. 2006
    ..In a subsequent paper (Schmidli et al., 2006) we give several applications from our daily practice and discuss related implementation issues in conducting adaptive seamless designs...
  61. ncbi Methodological quality of pharmacogenetic studies: issues of concern
    Andrea L Jorgensen
    Centre for Medical Statistics and Health Evaluation, The University of Liverpool, Shelley s Cottage, Brownlow Street, Liverpool L69 3GS, UK
    Stat Med 27:6547-69. 2008
    ..Some of these issues such as sample size and quality of genotypes(double dagger) have been given significant attention in the literature already whereas ..
  62. ncbi Towards power and sample size calculations for the comparison of two groups of patients with item response theory models
    Jean Benoit Hardouin
    UPRES EA 4275 Biostatistics, Clinical Research and Subjective Measures in Health Science, University of Nantes, France
    Stat Med 31:1277-90. 2012
    ..Item response theory (IRT) is an attractive way for PRO analysis. However, in the framework of IRT, sample size justification is rarely provided or ignores the fact that PRO measures are latent variables with the use of ..
  63. ncbi Sample size tables for exact single-stage phase II designs
    R P A'hern
    Department of Computing and Information, Royal Marsden NHS Trust, Fulham Road, London SW3 6JJ, UK
    Stat Med 20:859-66. 2001
    ..For example, if the upper success rate is accepted, the lower success rate, which the trial is designed to reject, may be included in the final confidence interval for the proportion being estimated...
  64. ncbi The size of a pilot study for a clinical trial should be calculated in relation to considerations of precision and efficiency
    Julius Sim
    Arthritis Research UK Primary Care Centre, Keele University, Keele, Staffordshire, UK
    J Clin Epidemiol 65:301-8. 2012
    ..To investigate methods to determine the size of a pilot study to inform a power calculation for a randomized controlled trial (RCT) using an interval/ratio outcome measure...
  65. ncbi Optimal design of multi-arm multi-stage trials
    James M S Wason
    Hub for Trials Methodology Research, MRC Biostatistics Unit, Cambridge, UK
    Stat Med 31:4269-79. 2012
    ..An optimal design has the required type I error rate and power but minimises the expected sample size at some set of treatment effects...
  66. pmc Adaptive trial designs: a review of barriers and opportunities
    John A Kairalla
    Department of Biostatistics, University of Florida, PO Box 117450, Gainesville, FL 32611 7450, USA
    Trials 13:145. 2012
    ..When adaptive designs are used properly, efficiencies can include a smaller sample size, a more efficient treatment development process, and an increased chance of correctly answering the clinical ..
  67. pmc Sample size determinations in original research protocols for randomised clinical trials submitted to UK research ethics committees: review
    Timothy Clark
    Institut für Medizinische Informationsverarbeitung, Biometrie und Epidemiologie, Faculty of Medicine, Ludwig Maximilians University, Munich, Germany
    BMJ 346:f1135. 2013
    To assess the completeness of reporting of sample size determinations in unpublished research protocols and to develop guidance for research ethics committees and for statisticians advising these committees.
  68. pmc Empirical tests of the reliability of phylogenetic trees constructed with microsatellite DNA
    Naoko Takezaki
    Life Science Research Center, Kagawa University, Japan
    Genetics 178:385-92. 2008
    ..To have reasonably high PC-values for trees similar to ours, at least 30 loci with a minimum of 15 individuals are required when DA distance is used...
  69. ncbi Randomizing patients by family practice: sample size estimation, intracluster correlation and data analysis
    Roxanne H Cosby
    Department of Family Medicine, McMaster University and Centre for the Evaluation of Medicines, St Joseph s Healthcare, Hamilton, Ontario, Canada
    Fam Pract 20:77-82. 2003
    ..Patients within a cluster may be similar to each other relative to patients in other clusters on key variables; therefore, sample size calculations and analyses of results require special statistical methods.
  70. pmc Intracluster correlation coefficients and coefficients of variation for perinatal outcomes from five cluster-randomised controlled trials in low and middle-income countries: results and methodological implications
    Christina Pagel
    Clinical Operational Research Unit, University College London, UK
    Trials 12:151. 2011
    ..This needs to be taken into account in sample size estimations for planned trials, but most estimates of intracluster correlation for perinatal health outcomes ..
  71. ncbi The detection of gene-environment interaction for continuous traits: should we deal with measurement error by bigger studies or better measurement?
    M Y Wong
    Department of Mathematics, The Hong Kong University of Science and Technology, Hong Kong
    Int J Epidemiol 32:51-7. 2003
    ..We have previously described power calculations for such studies, and this paper describes the extension of those calculations to take account of measurement error...
  72. pmc Unbiased comparison of sample size estimates from longitudinal structural measures in ADNI
    Dominic Holland
    Department of Neurosciences, University of California, San Diego, La Jolla, California 92037, USA
    Hum Brain Mapp 33:2586-602. 2012
    ..Here, using sample size estimates, we present a comparative analysis of the overall results that come from the application of each ..
  73. ncbi Empirical assessment suggests that existing evidence could be used more fully in designing randomized controlled trials
    Alison C Goudie
    Department of Health Sciences, University of Leicester, Leicester, Leicestershire, UK
    J Clin Epidemiol 63:983-91. 2010
    ..Meta-analyses of randomized controlled trials (RCTs) provide the highest level of evidence regarding the effectiveness of interventions. Less is known about how they are used to inform the design and reporting of RCTs...
  74. pmc Subregional neuroanatomical change as a biomarker for Alzheimer's disease
    Dominic Holland
    Department of Neurosciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
    Proc Natl Acad Sci U S A 106:20954-9. 2009
    ..The findings indicate that regional temporal lobe cortical changes would have great utility as outcome measures in clinical trials and may also have utility in clinical practice for aiding early diagnosis of neurodegenerative disease...
  75. ncbi Effects of interrater reliability of psychopathologic assessment on power and sample size calculations in clinical trials
    Matthias J Muller
    Department of Psychiatry, University of Mainz, Germany
    J Clin Psychopharmacol 22:318-25. 2002
    ..Implications of the reliability of psychiatric assessments for sample size and power calculations in clinical trials are presented...
  76. pmc Estimating required information size by quantifying diversity in random-effects model meta-analyses
    Jørn Wetterslev
    Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 3344, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK 2100 Copenhagen Ø, Denmark
    BMC Med Res Methodol 9:86. 2009
    ..The required information size in a meta-analysis may be calculated from an anticipated a priori intervention effect or from an intervention effect suggested by trials with low-risk of bias...
  77. ncbi Characteristics of clinical trials registered in ClinicalTrials.gov, 2007-2010
    Robert M Califf
    Duke Translational Medicine Institute, 200 Trent Dr, 1117 Davison Bldg, Durham, NC 27710, USA
    JAMA 307:1838-47. 2012
    ..Strengthened reporting requirements for studies registered with ClinicalTrials.gov enable a comprehensive evaluation of the national trials portfolio...
  78. pmc Designs for clinical trials with time-to-event outcomes based on stopping guidelines for lack of benefit
    Patrick Royston
    MRC Clinical Trials, London NW1 2DA UK
    Trials 12:81. 2011
    ..Such trials can terminate at any of the intermediate stages or the final stage...
  79. pmc Sample size requirements to detect gene-environment interactions in genome-wide association studies
    Cassandra E Murcray
    Department of Preventive Medicine, University of Southern California, Los Angeles, California 90089 9010, USA
    Genet Epidemiol 35:201-10. 2011
    ..15, and a binary exposure with prevalence 0.3, the Murcray, Kooperberg and hybrid methods are 1.90, 1.27, and 1.87 times as efficient, respectively, as the traditional case-control analysis to detect an interaction effect size of 2.0...
  80. ncbi Practical sample size calculations for surveillance and diagnostic investigations
    Geoffrey T Fosgate
    Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A and M University, College Station, TX 77843, USA
    J Vet Diagn Invest 21:3-14. 2009
    The likelihood that a study will yield statistically significant results depends on the chosen sample size. Surveillance and diagnostic situations that require sample size calculations include certification of disease freedom, estimation ..
  81. ncbi Increasing the sample size when the unblinded interim result is promising
    Y H Joshua Chen
    Merck Research Laboratories, Blue Bell, PA 19422, USA
    Stat Med 23:1023-38. 2004
    Increasing the sample size based on unblinded interim result may inflate the type I error rate and appropriate statistical adjustments may be needed to control the type I error rate at the nominal level...
  82. pmc Two-stage designs optimal under the alternative hypothesis for phase II cancer clinical trials
    A P Mander
    MRC Biostatistics Unit Hub for Trials Methodology Research, Institute of Public Health, Robinson Way, Cambridge, CB2 0SR, United Kingdom
    Contemp Clin Trials 31:572-8. 2010
    ..conventional optimal design, for given type 1 and type 2 error rates, is the one which minimises the expected sample size under the null hypothesis...
  83. pmc Published methodological quality of randomized controlled trials does not reflect the actual quality assessed in protocols
    Rahul Mhaskar
    Division and Center for Evidence Based Medicine and Outcomes Research, Department of Internal Medicine, Clinical and Translational Science Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
    J Clin Epidemiol 65:602-9. 2012
    To assess whether the reported methodological quality of randomized controlled trials (RCTs) reflects the actual methodological quality and to evaluate the association of effect size (ES) and sample size with methodological quality.
  84. pmc Relative power and sample size analysis on gene expression profiling data
    M van Iterson
    Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
    BMC Genomics 10:439. 2009
    ..researchers today are confronted with choosing the technology that has sufficient power with minimal sample size, in order to reduce cost and time...
  85. ncbi Sample size slippages in randomised trials: exclusions and the lost and wayward
    Kenneth F Schulz
    Family Health International, PO Box 13950, Research Triangle Park, NC 27709, USA
    Lancet 359:781-5. 2002
    ..Unfortunately, some explanations for mishandling exclusions intuitively appeal to readers, disguising the seriousness of the issues. Creative mismanagement of exclusions can undermine trial validity...
  86. ncbi Literature review: considerations in undertaking focus group research with culturally and linguistically diverse groups
    Elizabeth J Halcomb
    Centre for Applied Nursing Research, University of Western Sydney and Sydney South West Area Health Service, Liverpool, NSW, Australia
    J Clin Nurs 16:1000-11. 2007
    ..This integrated literature review seeks to identify the key considerations in conducting focus groups and discusses the specific considerations for focus group research with culturally and linguistically diverse groups...
  87. ncbi A three-outcome design for phase II clinical trials
    D J Sargent
    Section of Biostatistics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
    Control Clin Trials 22:117-25. 2001
    ..We describe the theoretical properties of this design and illustrate it with several examples. We focus on the clinical implications of the three-outcome design. Control Clin Trials 2001;22:117-125..
  88. ncbi Sample size calculations in surgery: are they done correctly?
    Melinda A Maggard
    UCLA School of Medicine and the West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90095, USA
    Surgery 134:275-9. 2003
    ..b>Sample size calculations are essential for planning a study to minimize both type I and type II errors...
  89. ncbi Randomised controlled trials in overweight children: practicalities and realities
    Janet M Warren
    University of Newcastle, Schools of Health Sciences and Education, Callaghan Campus, Newcastle, New South Wales, Australia
    Int J Pediatr Obes 2:73-85. 2007
    ..To highlight and discuss the practical aspects of conducting high quality, randomised controlled trials (RCTs) with overweight and obese children and their families...
  90. ncbi The use of unequal randomisation ratios in clinical trials: a review
    J C Dumville
    Area 4, York Trials Unit, Department of Health Sciences, University of York, York, YO10 5DD, United Kingdom
    Contemp Clin Trials 27:1-12. 2006
    ..To examine reasons given for the use of unequal randomisation in randomised controlled trials (RCTs)...
  91. pmc The HAART cell phone adherence trial (WelTel Kenya1): a randomized controlled trial protocol
    Richard T Lester
    Department of Medical Microbiology, University of Nairobi, UNITID Building, Nairobi, Kenya
    Trials 10:87. 2009
    ..The objectives are to compare the effectiveness of cell phone-supported SMS messaging to standard care on adherence, quality of life, retention, and mortality in a population receiving antiretroviral therapy (ART) in Nairobi, Kenya...
  92. ncbi Candidate gene studies of human pain mechanisms: methods for optimizing choice of polymorphisms and sample size
    Inna Belfer
    Pain and Neurosensory Mechanisms Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
    Anesthesiology 100:1562-72. 2004
  93. ncbi Implementation challenges to using respondent-driven sampling methodology for HIV biological and behavioral surveillance: field experiences in international settings
    Lisa Grazina Johnston
    School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
    AIDS Behav 12:S131-41. 2008
    ..We explored factors for poor study outcomes using differences in mean sample size ratios (recruited/calculated sample size) as the outcome variable...
  94. pmc Did modeling overestimate the transmission potential of pandemic (H1N1-2009)? Sample size estimation for post-epidemic seroepidemiological studies
    Hiroshi Nishiura
    PRESTO, Japan Science and Technology Agency, Saitama, Japan
    PLoS ONE 6:e17908. 2011
    ..Seroepidemiological studies before and after the epidemic wave of H1N1-2009 are useful for estimating population attack rates with a potential to validate early estimates of the reproduction number, R, in modeling studies...
  95. ncbi Cluster trials in implementation research: estimation of intracluster correlation coefficients and sample size
    M K Campbell
    Health Services Research Unit, University of Aberdeen, Aberdeen, UK
    Stat Med 20:391-9. 2001
    ..design considerations specific to implementation research studies, focusing particularly on the estimation of sample size requirements and on the need for reliable information on intracluster correlation coefficients for both ..
  96. ncbi Exploiting gene-environment interaction to detect genetic associations
    Peter Kraft
    Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
    Hum Hered 63:111-9. 2007
    ..We compare the power and sample size requirements of this joint test to other analyses: the marginal test of genetic association, the standard test ..
  97. ncbi Sample size requirements for estimating intraclass correlations with desired precision
    Douglas G Bonett
    Department of Statistics, Iowa State University, Snedecor Hall, Ames, IA 50011 1210, USA
    Stat Med 21:1331-5. 2002
    ..The sample size approximation is shown to be very accurate.
  98. pmc LOST to follow-up Information in Trials (LOST-IT): a protocol on the potential impact
    Elie A Akl
    Department of Medicine, State University of New York at Buffalo, Buffalo, USA
    Trials 10:40. 2009
    ..The secondary objectives are to describe, for published RCTs, (1) the reporting of loss to follow-up information, (2) the analytic methods used for handling loss to follow-up information, and (3) the extent of reported loss to follow-up...
  99. pmc Current sample size conventions: flaws, harms, and alternatives
    Peter Bacchetti
    Department of Epidemiology and Biostatistics, University of California, San Francisco, CA 94143, USA
    BMC Med 8:17. 2010
    ..The belief remains widespread that medical research studies must have statistical power of at least 80% in order to be scientifically sound, and peer reviewers often question whether power is high enough...
  100. ncbi Sample size calculations for randomized controlled trials
    Janet Wittes
    Statistics Collaborative, Inc, 1710 Rhode Island Avenue NW, Suite 200, Washington, DC 20036, USA
    Epidemiol Rev 24:39-53. 2002
  101. pmc Design, analysis and presentation of factorial randomised controlled trials
    Alan A Montgomery
    Division of Primary Health Care, University of Bristol, Cotham House, Cotham Hill, Bristol BS6 6JL, UK
    BMC Med Res Methodol 3:26. 2003
    ..However this requires increased sample size and can be inefficient, especially if there is also interest in considering combinations of the interventions...

Research Grants80

  1. Reducing Obesity & Diabetes in High Risk Youth
    ROBIN G WHITTEMORE; Fiscal Year: 2010
    ..No youth will be excluded from participation, yielding a potential sample size of nearly 900...
  2. Understanding/ Treating Neuropsychiatric Symptoms of Pediatric Physical Illness
    Eva Szigethy; Fiscal Year: 2009
    ..abstract_text> ..
  3. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    BARBARA O'BRIEN; Fiscal Year: 2013
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  4. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    Mona Fouad; Fiscal Year: 2013
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: [unreadable] Large sample size allows statistical power [unreadable] Specimens are collected prospectively, before cancer diagnosis [..
  5. Osteocalcin and Metabolic Risk Factors. The Framingham Study
    Yi Hsiang Hsu; Fiscal Year: 2011
    ..The proposed work will take advantage of the rich available data and large sample size of the Framingham Heart Study...
  6. Predictors of Pregnancy Outcome in SLE and APS
    Jane E Salmon; Fiscal Year: 2012
    ..We propose to increase our target sample size from 400 to 700 pregnant patients to maintain study power given lower than expected outcome rates, and to ..
  7. Exome re-sequencing candidate loci for familial essential tremor
    Barry E Kosofsky; Fiscal Year: 2012
    ..A power analysis estimates that the sample size required to detect mutations with 95% confidence are 10 affected individuals with a disease haplotype and 10 ..
  8. Epistasis in Steroidogenic Genes in the Prediction of Alzheimer's Disease
    CRAIG STEPHEN ATWOOD; Fiscal Year: 2013
    ..This grant therefore aims to perform genotype and hormone analyses in a larger sample size to gain greater confidence that these interactions are important predictors of AD...
  9. Plasma Lipid Markers and Cancer Risk
    Lu Wang; Fiscal Year: 2013
    ..This study also has numerous other strengths, including the prospective cohort study design, large sample size (n = 28,345), large numbers of cases (n = 3,506), long duration of follow-up (17 years), excellent environment, ..
  10. Biochemical, Biomechanical & Morphological Properties of Quantitative Ultrasound
    Barbara L McFarlin; Fiscal Year: 2010
    ..design consisting of 2 experiments to achieve aim 1 consisting of: a preliminary experiment (1) to determine sample size and a more definitive experiment (2)...
  11. RRSS #08: Evaluating Prevalence HPV Infection Among Head and Neck Cancer Patients
    Dennis M Deapen; Fiscal Year: 2009
    ..use of HPV type specific vs. universal primers, and sample size and composition. PCR is consider more sensitive than the other testing methods...
  12. Statins for Pulmonary and Cardiac Complications of Chronic HIV (The SPARC Trial)
    Stephen R Wisniewski; Fiscal Year: 2013
    ..effects of rosuvastatin compared to placebo in an adaptive response design to determine effect size, estimate sample size, and develop a novel composite endpoint in preparation for a full-scale trial...
  13. A Clinical Trial to Prevent New Onset Diabetes After Transplantation
    Akinlolu O Ojo; Fiscal Year: 2013
    ..A sample size of 180 KTRs has a 90% power to detect a 30% risk reduction for NODAT at one-year post transplantation after ..
  14. PERL: A multicenter clinical trial of allopurinol to prevent GFR loss in T1D
    S MICHAEL MAUER; Fiscal Year: 2013
    ..b>Sample size calculations under various dropout and non- adherence scenarios suggest that 240 subjects in each treatment arm ..
  15. L-carnitine Treatment for Vasopressor Dependent Septic Shock
    Alan E Jones; Fiscal Year: 2013
    ..protection against false positive results, and allow for dose finding, all while maintaining a manageable sample size. Our second aim is to assess if L-carnitine improves blood flow in the sublingual microvasculature during ..
  16. Planning a clinical trial of Flash-heated breast milk to decrease morbidity, impr
    Caroline J Chantry; Fiscal Year: 2010
    ..planning period will allow travel to Tanzania to define collaborative arrangements;finalize study design and sample size;choose study sites;attempt to secure funding;the design, translation and piloting of data collection ..
  17. Impact of adipokines and insulin resistance on progression of prehypertension
    Cynthia Cheng; Fiscal Year: 2013
    ..Prior microcirculation research in hypertension has been limited by sample size, the lack of inclusion of minority populations such as African-Americans, an ethnic population at high risk for ..
  18. Scleroderma Subtyping from Fresh and Archived Biopsies using NextGen Sequencing
    Michael W Fanger; Fiscal Year: 2011
    ..Aim 2. Increase the quality and sample size of clinical longitudinal data using either UHTS or Nanostring and analyze the clinical covariates associated ..
  19. Transfusion Trigger Trial in Coronary Artery Disease: A Pilot Study
    JEFFREY LEE CARSON; Fiscal Year: 2010
    ..d. To determine frequencies of proposed outcomes in anemic CAD patients to use for calculating sample size for large definitive trial...
  20. Longitudinal Studies of Autism Spectrum Disorders: 2 to 23
    Catherine Lord; Fiscal Year: 2012
    ..and adolescents with a current diagnosis (CDX) between the ages of 9 and 23 will be recruited to increase sample size and power...
  21. IeDEA West -Africa collaboration
    Francois Dabis; Fiscal Year: 2013
    ..Our five-year research plan will focus on scientific questions requiring a large sample size of patients that the contributing cohorts cannot answer individually and which do not overlap with existing ..
  22. Biological Markers of Aflatoxin Exposure and Methylation
    Regina M Santella; Fiscal Year: 2013
    ..The larger sample size will provide more statistical power to test new hypotheses related to methylation and HCC risk...
  23. Genome-wide and Linkage Study of Quantitative Emphysema Phenotypes
    Stephen S Rich; Fiscal Year: 2010
    ..This sample size, however, is adequate to detect only large associations at GWAS levels of significance...
  24. Phase 2 Study of High Dose DHA for the Treatment of X-Linked Retinitis Pigmentosa
    Dennis R Hoffman; Fiscal Year: 2013
    ..With a sample size of 55 active participants, 24 subjects per group (placebo and DHA-supplemented) have remained to attain ..
  25. Virtual World Health Behavior Counseling for Patients with Diabetes
    JOHN MOORE contact WIECHA; Fiscal Year: 2010
    ..the intervention;3) Document baseline values and variance of outcome variables in order to accurately estimate sample size and statistical power in a subsequent RCT...
  26. Outcomes of Community Naturopathic Medical Care for Type 2 Diabetes
    Daniel C Cherkin; Fiscal Year: 2010
    ..A sample size of 30 participants will provide over 90% power to detect a 1.0 percentage point decrease in mean HbA1c...
  27. Dialysis Infection and Vitamin D in New England: The DIVINE Study
    Ravi Thadhani; Fiscal Year: 2012
    ..To directly address this, we are performing a double-blind, placebo-controlled randomized trial in 105 (new sample size) incident chronic hemodialysis patients (35/arm x 3) with 25D insufficiency (<30ng/ml), comparing two ..
  28. Predictors of Treatment Response Relapse and Recurrence in Major Depression
    W Edward Craighead; Fiscal Year: 2012
    ..is an expansion of our recently funded NIMH CIDAR 3-arm, 12-week treatment trial;we will increase the CIDAR sample size from 400 to 600 and follow all remitted patients for a total of two years...
  29. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    Mona Fouad; Fiscal Year: 2010
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: Large sample size allows statistical power Specimens are collected prospectively, before cancer diagnosis Serial specimens are ..
  30. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    BARBARA O apos BRIEN; Fiscal Year: 2010
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  31. PROSTATE, LUNG, COLORECTAL AND OVARIAN (PLCO) CANCER SCREENING TRIAL
    Paul Kvale; Fiscal Year: 2010
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  32. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    Mona Fouad; Fiscal Year: 2011
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: Large sample size allows statistical power Specimens are collected prospectively, before cancer diagnosis Serial specimens are ..
  33. Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial - Lab
    Cheryl Robinson; Fiscal Year: 2009
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  34. PROSTATE, LUNG, COLORECTAL AND OVARIAN (PLCO) CANCER SCREENING TRIAL
    Claudine Isaacs; Fiscal Year: 2009
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  35. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    BARBARA O apos BRIEN; Fiscal Year: 2009
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  36. PROSTATE, LUNG, COLORECTAL AND OVARIAN (PLCO) CANCER SCREENING TRIAL
    KAREN STEINMETZ; Fiscal Year: 2011
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  37. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    BARBARA O'BRIEN; Fiscal Year: 2011
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  38. PROSTATE, LUNG, COLORECTAL AND OVARIAN (PLCO) CANCER SCREENING TRIAL
    Claudine Isaacs; Fiscal Year: 2010
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  39. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    Saundra Buys; Fiscal Year: 2009
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: - Large sample size allows statistical power - Specimens are collected prospectively, before cancer diagnosis - Serial specimens ..
  40. Prostate, Lung, Colorectal and Ovarian (PLCO) Screening Trial
    Mona Fouad; Fiscal Year: 2009
    ..Some of the characteristics that make the PLCO biospecimens uniquely valuable include: [unreadable] Large sample size allows statistical power [unreadable] Specimens are collected prospectively, before cancer diagnosis [..
  41. Transdermal Delivery of Deferoxamine to Prevent and Treat Diabetic Wounds
    Geoffrey C Gurtner; Fiscal Year: 2011
    ..then conduct biostatistical analyses to confirm the feasibility of our outcome measures and begin to develop sample size calculations;this will permit us to begin building a rudimentary trial design in accordance with an eventual ..
  42. Long-Term Safety and Genetic Risk Factors of Risperdone Treatment in Youth
    Chadi A Calarge; Fiscal Year: 2010
    ..Thus, during the two-year period of this study, we propose to increase the current sample size and reevaluate all the patients, 15 months after their baseline enrollment...
  43. Furlow Palatoplasty with Tensor Tenopexy for Otitis Media
    Joseph E Losee; Fiscal Year: 2013
    ..Our sample size of 120 was chosen to allow for a drop-out of 25% by 7 years of age and, thus, to retain statistical power to ..
  44. Meditation and Exercise for Prevention of Acute Respiratory Infection
    Bruce P Barrett; Fiscal Year: 2010
    ..b>Sample size will be N=333, with N=111 in each group...
  45. The Charge Study: Childhood Autism Risks from Genetics and the Environment
    Irva Hertz-Picciotto; Fiscal Year: 2013
    ..To ensure adequate power for this analysis of gene-environment interaction, the sample size will be increased to 2400 children...
  46. Molecular Epidemiology of non-Hodgkin Lymphoma Survival
    James R Cerhan; Fiscal Year: 2010
    ..This resource has several methodologic strengths, including large sample size (>2200cases), central pathology review and classification, availability of tumor tissue, detailed baseline ..
  47. Etiology of breast development in the BCERC network: role of socioeconomic status
    DEJANA K BRAITHWAITE; Fiscal Year: 2010
    ..The large sample size of the BCERC network, including the data already collected via extensive longitudinal assessments of a ..
  48. Ameliorating Sickle Nephropathy and Pulmonary Hypertension
    Punam Malik; Fiscal Year: 2013
    ..pilot studies will help estimate feasibility of accruing patients, determine a refined duration/dose and the sample size and response rate necessary in the first two years of funding...
  49. Multi-Ethnic Study of Autoimmunity and Cardiovascular Disease
    Darcy S Majka; Fiscal Year: 2013
    ..The large sample size and the evaluation of autoantibodies will allow the principal investigator to address the unique hypothesis ..
  50. Impact of Sunflower Oil Massage on Neonatal Mortality in Nepal
    Luke C Mullany; Fiscal Year: 2013
    ..To detect a 20% reduction in all-cause neonatal mortality with 90% power and Type I error of 5%, the required sample size per group is 13,601. This sample size accounts for the clustered design and 5% loss to follow up...
  51. Phase II/III Study of Arimoclomol in the Treatment of SOD1 Positive Familial?.
    Merit E Cudkowicz; Fiscal Year: 2013
    ..The analysis of this stage-1 data will also be used to re-estimate the sample size required for the second stage of the study that will include approximately an additional 50 subjects, followed ..
  52. Identification of Psoriatic Arthritis Genes
    JAMES TILFORD ELDER; Fiscal Year: 2013
    ..controls, forged a collaboration with PsA experts Dafna Gladman and Proton Rahman that greatly increased our sample size, and generated a wealth of MHC SNP genotyping data in our recent genome-wide association scan (GWAS), the ..
  53. A CENTER OF MOLECULAR DEVELOPMENTAL HEMATOPOIESIS
    Stuart H Orkin; Fiscal Year: 2013
    ..In parallel, CORE C will explore and then disseminate approaches to minimize sample size in an effort to facilitate genomic and epigenetic studies on limited populations, such as HSCs...
  54. Genetic and estrogen-dependent regulation of the human PAC1R receptor and PTSD
    Kerry J Ressler; Fiscal Year: 2013
    ..This proposal aims to extend these initial findings with a larger sample size, identifying peripheral markers of PACAP/PAC1 pathway activity as a biomarker for PTSD...
  55. Whole Genome Association Analysis of Hematopoietic Cell Transplant (HCT) Outcome
    JOHN ANDREW HANSEN; Fiscal Year: 2013
    ..Increasing the sample size by >300% will improve power for detecting genetic variants associated with HCT outcomes across a range of ..
  56. 2/3 CBT for Anxiety Disorders in Autism: Adapting Treatment for Adolescents
    Eric A Storch; Fiscal Year: 2010
    ..incorporating all the features of the planned future efficacy trial comparing CBT and RT, but with a limited sample size (N = 48)...
  57. Cohort Study of Genetic Susceptibility to Cutaneous Malignant Melanoma
    Jiali Han; Fiscal Year: 2010
    ..well-characterized cohorts, including cohort characteristics, quality of design, high follow-up rate, large sample size, prospective host factor assessment, and high response rate of retrospective questionnaires...
  58. Determinants of Participation in an Anal Cancer Prevention Trial
    Joel Palefsky; Fiscal Year: 2010
    ..To determine the optimum study design and sample size, and recruitment strategies based on the analysis of data from Aims 1 and 2...
  59. Improving substance abuse counseling adherence using web-based videoconferencing
    Van L King; Fiscal Year: 2010
    ..eGetgoing treatment delivery in an OTP setting and only failed to reach statistical significance because of low sample size (insufficient power)...
  60. Shared Decision-Making in End-Stage Heart & Lung Disease
    Mark Sullivan; Fiscal Year: 2005
    ..In our revised proposal, we have omitted our follow-up interviews in order to expand our sample size and maximize the diversity of our subjects...
  61. Race Related Stressors and Preterm Birth in African American Women
    Carmen Giurgescu; Fiscal Year: 2009
    ..and perceived neighborhood environment;(4) variability of the predictors for use in power analyses for sample size in a larger study;(5) exploring differences in race-related stressors, personal resources, and stress responses ..
  62. Zinc-Based Early Detection of Prostate Cancer
    Christopher J Frederickson; Fiscal Year: 2010
    ..Our Phase II study has two components. In Study IIA we will increase our sample size to better estimate the sensitivity and specificity of our test...
  63. IMPROVING GAIT AND FUNCTION IN CP BY STRENGTHENING THE ANKLE
    Jack Engsberg; Fiscal Year: 2009
    ..The purpose of this proposed phase II clinical trial is to establish sample size requirements for a phase III clinical trial to determine if ankle strength increases in the plantarflexors can ..
  64. FOUR TREATMENT STRATEGIES FOR TMJ DISK DISPLACEMENT
    Eric Schiffman; Fiscal Year: 2002
    ..This study is the first RCT with an adequate sample size to assess the relative short-term effectiveness of current treatment strategies for subjects with a symptomatic,..
  65. Discovery of exon, microRNA and clinical prognostic markers of glioblastoma survi
    SANDRA L RODRIGUEZ ZAS; Fiscal Year: 2010
    ..framework encompasses the simultaneously consideration clinical and genomic information, use of a large sample size including 397 glioblastoma and matched control samples, and a comprehensive analysis of the relationship ..
  66. Msec Polymerase Chain Reaction with fMolar Detection Sensitivity using SPR
    DONALD ROPER; Fiscal Year: 2007
    ..But speed, sensitivity and sample size of PCR are constrained by slow thermal response times and low absorption cross-sections for fluorescent labels, ..
  67. Folate, Smoking, Race and Cervical Cancer Risk
    Capri Mara Fillmore; Fiscal Year: 2004
    ..By improving study design, increasing sample size, utilizing dietary folate equivalents (DFEs) and homocysteine levels (a functional marker of folate sufficiency)..
  68. A 3-D Interactive Atlas of the Maxilla, Mandible & TMJ
    William Brown; Fiscal Year: 2006
    ..While the VHP represent a landmark effort, it suffers from limited sample size, (two subjects), resolution and segmentation problems...
  69. COGNITIVE AND NEUROIMAGING STUDY OF SICKLE CELL ANEMIA
    Elias Melhem; Fiscal Year: 2001
    ..This pilot will provide us with the statistical parameters necessary to determine an adequate sample size needed to specify the factors contributing to neuropsychological impairment seen in children with Sickle Cell ..
  70. High Efficiency Screening of Bioactive Lipids
    MITCHELL JOHNSON; Fiscal Year: 2009
    ..samples, and couple it directly to a two-dimensional capillary liquid chromatography system that matches the sample size with the sensitivity of modern electrospray mass spectrometry...
  71. Rituximab for Treatment of Type 1 Diabetes: Impact on JC Viral Proliferation
    MARK DAVID PESCOVITZ; Fiscal Year: 2010
    ..However, the small sample size (46 rituximab-treated subjects) limits the ability to generalize this conclusion to rare opportunistic ..
  72. PATHOBIOLOGY OF BREAST CANCER AND HORMONE RECEPTORS
    Michael Press; Fiscal Year: 2003
    ..Issues related to study design, especially sample size, sensitivity and specificity of analytic methods used for gene amplification / overexpression and the potential ..
  73. Reducing Risk in Cardiac Rehabilitation: Partners Together in Health (PaTH) Inter
    Bernice Yates; Fiscal Year: 2009
    ..all outcome variables in both the CABG patient and the partner to estimate effect sizes needed to determine the sample size requirements for the larger study...