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Activity Number:
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65
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Type:
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Contributed
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Date/Time:
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Sunday, July 29, 2007 : 4:00 PM to 5:50 PM
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Sponsor:
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Biopharmaceutical Section
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| Abstract - #309299 |
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Title:
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Extension of the Rank Sum Test for Clustered Data in Vision Clinical Trials
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Author(s):
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Ratna Ramaswamy*+ and Gary Koch and Ram Ganeshan
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Companies:
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Johnson & Johnson PRD and The University of North Carolina at Chapel Hill and Statistical Consultant
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Address:
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199 Grandview Road, Skillman, NJ, 08502,
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Keywords:
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Wilcoxon Type Nonparametric Rank Tests ; Vision Trials ; Non-Independence among experimental Units
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Abstract:
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In Vision Clinical trials, the unit of drug treatment is one of the two eyes. To make the maximum use of the experimental units eye is considered as unit of analysis. Only the case of two treatments, active and vehicle placebo is considered here for simplicity. Clinical parameters of interest as an example would be itching and redness measured on the ordinal scale. For the nature of the data (generally, non-normal and skew distributed), a rank test such as two-sample Wilcoxon Rank Sum Test comes out as the test of choice. However the factor of non-independence of the sampling units (eyes) is generally ignored. Some reasonable ranking methods using Cochran-Mantel-Haenzel tests that would take the correlated structure of the data into consideration are given here.
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