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Activity Number:
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519
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Type:
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Invited
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Date/Time:
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Thursday, August 2, 2007 : 10:30 AM to 12:20 PM
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Sponsor:
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WNAR
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| Abstract - #307989 |
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Title:
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Contamination and Group Randomized Trials
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Author(s):
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Ziding Feng*+
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Companies:
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Fred Hutchinson Cancer Research Center
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Address:
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1100 Fairview Ave N, M2-B500, Seattle, WA, 98109,
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Keywords:
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Contamination ; Group Randomized Trials
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Abstract:
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Investigators often automatically use group randomized trials when faced with the possibility of contamination across subjects within a group. However, the bias due to contamination always makes the observed intervention effect smaller, leading to conservative rather than spurious findings. Therefore the efficiency is the central issue. It has been suggested (Torgerson, 2001) that individual randomized trials may nevertheless be more efficient despite the contamination. We present models for contamination that allow quantification of the dilution of effect size versus the lower cost of individual randomized trials as a function of GRT design parameters, such as the ICC. This will allow calculation of the degree of contamination necessary to make a GRT more efficient and aid researchers in avoiding GRTs when they are unnecessary and not cost-effective.
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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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