A new approach for within-subject mediation analysis in AB/BA crossover designs
- Author
- Haeike Josephy, Tom Loeys (UGent) and Stijn Vansteelandt (UGent)
- Organization
- Abstract
- Crossover trials are widely used in psychological and medical research to assess the effect of reversible exposures. In such designs, each subject is randomly allocated to a sequence of conditions, enabling the evaluation of treatment differences within each individual. When there are but two possible exposures -each assessed during one of two time periods-, the crossover study is referred to as an AB/BA design. The goal of this presentation is to discuss mediation analysis in such simple crossover studies. We do so by considering within-subject mediation from a counterfactual-based perspective and by deriving expressions for the direct and indirect effects. Employing simulation studies, the performance of several existing methods will be assessed and compared to that of a novel one we propose. We show that the new method yields unbiased and efficient estimators for the direct and indirect effect, under a minimalistic set of `no unmeasured confounding'-assumptions. Finally, we illustrate the different techniques with data from a neurobehavioral study.
- Keywords
- Counterfacuals, AB/BA, Madiation analysis
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Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-4443399
- MLA
- Josephy, Haeike, et al. “A New Approach for Within-Subject Mediation Analysis in AB/BA Crossover Designs.” Belgian Statistical Society, 21st Meeting, Abstracts, 2013.
- APA
- Josephy, H., Loeys, T., & Vansteelandt, S. (2013). A new approach for within-subject mediation analysis in AB/BA crossover designs. Belgian Statistical Society, 21st Meeting, Abstracts. Presented at the 21st Meeting of the Belgian Statistical Society, Ghent, Belgium.
- Chicago author-date
- Josephy, Haeike, Tom Loeys, and Stijn Vansteelandt. 2013. “A New Approach for Within-Subject Mediation Analysis in AB/BA Crossover Designs.” In Belgian Statistical Society, 21st Meeting, Abstracts.
- Chicago author-date (all authors)
- Josephy, Haeike, Tom Loeys, and Stijn Vansteelandt. 2013. “A New Approach for Within-Subject Mediation Analysis in AB/BA Crossover Designs.” In Belgian Statistical Society, 21st Meeting, Abstracts.
- Vancouver
- 1.Josephy H, Loeys T, Vansteelandt S. A new approach for within-subject mediation analysis in AB/BA crossover designs. In: Belgian Statistical Society, 21st Meeting, Abstracts. 2013.
- IEEE
- [1]H. Josephy, T. Loeys, and S. Vansteelandt, “A new approach for within-subject mediation analysis in AB/BA crossover designs,” in Belgian Statistical Society, 21st Meeting, Abstracts, Ghent, Belgium, 2013.
@inproceedings{4443399,
abstract = {{Crossover trials are widely used in psychological and medical research to assess the effect of reversible exposures. In such designs, each subject is randomly allocated to a sequence of conditions, enabling the evaluation of treatment differences within each individual. When there are but two possible exposures -each assessed during one of two time periods-, the crossover study is referred to as an AB/BA design. The goal of this presentation is to discuss mediation analysis in such simple crossover studies. We do so by considering within-subject mediation from a counterfactual-based perspective and by deriving expressions for the direct and indirect effects. Employing simulation studies, the performance of several existing methods will be assessed and compared to that of a novel one we propose. We show that the new method yields unbiased and efficient estimators for the direct and indirect effect, under a minimalistic set of `no unmeasured confounding'-assumptions. Finally, we illustrate the different techniques with data from a neurobehavioral study.}},
author = {{Josephy, Haeike and Loeys, Tom and Vansteelandt, Stijn}},
booktitle = {{Belgian Statistical Society, 21st Meeting, Abstracts}},
keywords = {{Counterfacuals,AB/BA,Madiation analysis}},
language = {{eng}},
location = {{Ghent, Belgium}},
title = {{A new approach for within-subject mediation analysis in AB/BA crossover designs}},
year = {{2013}},
}