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Activity Number:
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296
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Type:
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Roundtables
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Date/Time:
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Tuesday, July 31, 2007 : 12:30 PM to 1:50 PM
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Sponsor:
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Biopharmaceutical Section
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| Abstract - #309923 |
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Title:
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Blinded Sample Size Re-estimation
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Author(s):
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Biao Xing*+
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Companies:
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Genentech, Inc.
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Address:
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1 DNA Way, South San Francisco, CA, 94080,
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Keywords:
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Sample Size ; Power ; Adaptive Design
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Abstract:
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Blinded sample size re-estimation allows for modifying the sample size of an ongoing trial to ensure sufficient statistical power without breaking the blind. One challenge is the blinded estimation of the within group variance. Early proposed methods either make untenable assumptions or are only applicable to two-treatment trials. Moreover, these methods are often biased. We propose a simple, unbiased method, that also makes minimal assumptions. The method uses the enrollment order of subjects and the randomization block size to estimate the variance and then re-estimate the sample size. It can be applied to normal or non-normal data, to trials with two or more arms, equal or unequal allocation schemes, and fixed or random randomization block sizes. Results from simulations and data analysis suggest the proposed blinded sample size estimation approach is practical.
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- The address information is for the authors that have a + after their name.
- Authors who are presenting talks have a * after their name.
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