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Fig. 1 | BMC Medical Research Methodology

Fig. 1

From: Noncollapsibility and its role in quantifying confounding bias in logistic regression

Fig. 1

Directed acyclic graphs of the four possible scenarios into which each simulated condition can be classified. Panel A: both confounding and noncollapsibility. Panel B: confounding without noncollapsibility. Panel C: noncollapsibility without confounding. Panel D: neither confounding nor noncollapsibility. C represents three continuous covariates, X represents the dichotomous exposure and Y represents the dichotomous outcome. The dotted line in panel D between the covariates and the exposure and between the exposure and the outcome indicate there may or may not be an association

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