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Activity Number:
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199
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Type:
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Contributed
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Date/Time:
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Monday, August 7, 2006 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Statistics in Epidemiology
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| Abstract - #306809 |
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Title:
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On the Equivalence of Case-Crossover and Time-Series Methods
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Author(s):
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Yun Lu*+ and Scott Zeger
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Companies:
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Johns Hopkins University and Johns Hopkins University
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Address:
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734 Concord Point Drive, Perryville, MD, 21903,
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Keywords:
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time series ; case-crossover design ; log-linear model ; Poisson regression ; environmental epidemiology ; air pollution
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Abstract:
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Time series and case-crossover methods are often viewed as competing alternatives in environmental epidemiologic studies. Several recent studies have compared the time series and case-crossover methods. In this paper, we show that case-crossover using conditional logistic regression is a special case of time series analysis when there is a common exposure such as in air pollution studies. This equivalence provides computational convenience for case-crossover analyses and a better understanding of time series models. Time series log-linear regression accounts for over-dispersion of the Poisson variance, while case-crossover analyses typically do not. This equivalence also permits model checking for case-crossover data using standard log-linear model diagnostics.
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