1. The power to detect an OR of 2
The power to detect an OR of 2.0 for the association between prevalent HPV detection and host immune status, comparing HIV-positive women with CD4+ count <200 cells/mm3(n = 535) versus >500 cells/mm3 (n = 458) under various conditions: (a) using data from o...
The power to detect an OR of 2.0 for the association between prevalent HPV detection and host immune status, comparing HIV-positive women with CD4+ count <200 cells/mm3(n = 535) versus >500 cells/mm3 (n = 458) under various conditions: (a) using data from only a single observation (J = 1; equivalent to standard logistic regression), (b) using data from 5 or 10 repeated study visits per observations (J = 5, J = 10), and (c) assuming the correlation between repeated observations is moderate (correlation = 0.3) or very high (correlation = 0.6). The figure shows greater statistical power for models that incorporate a GEE, and use data from multiple observations, compared with standard logistic regression models, which can only use data from a single observation.
Xiaonan Xue et al. Cancer Epidemiol Biomarkers Prev 2010;19:
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