Statistical Note: Confounding and Causality in Observational Studies

Residual confounding in observational studies.

To the Editor:—I read the study by Fellahi JL et al. titled “Perioperative use of dobutamine in cardiac surgery and adverse cardiac outcome” with great interest. This study showed that the use of dobutamine was associated with adverse outcomes in adult cardiac surgery, and the authors concluded that these results suggest that dobutamine should only be administered when the benefit is judged to ...

Confounding in Observational Studies Explained

Practical and ethical constraints mean that many clinical and/or epidemiological questions cannot be answered through the implementation of a randomized controlled trial. Under these circumstances, observational studies are often required to assess relationships between certain exposures and disease outcomes. Unfortunately, observational studies are notoriously vulnerable to the effect of diffe...

Residual Confounding in Observational Studies

To the Editor:—I read the study by Fellahi JL et al. titled “Perioperative use of dobutamine in cardiac surgery and adverse cardiac outcome” with great interest. This study showed that the use of dobutamine was associated with adverse outcomes in adult cardiac surgery, and the authors concluded that these results suggest that dobutamine should only be administered when the benefit is judged to ...

Confounding Equivalence in Observational Studies

Causality, Confounding, and Control

In a previous paper, Russo et al. (2006), causality is considered in the framework of structural models, i.e. statistical models characterized by parameters that are stable over a large class of interventions or of environmental changes and that take into account background and contextual knowledge. From this statistical viewpoint, causality is defined in terms of exogeneity in a structural mod...