Citation

Vanderweele TJ. Biometrics 2008; 64(3): 702-706.

Affiliation

Department of Health Studies, University of Chicago, 5841 South Maryland Avenue, MC 2007, Chicago, Illinois 60637, USA. vanderweele@uchicago.edu

Copyright

(Copyright © 2008, Biometric Society, Publisher John Wiley and Sons)

DOI

10.1111/j.1541-0420.2007.00957.x

PMID

18177462

Abstract

Unmeasured confounding variables are a common problem in drawing causal inferences in observational studies. A theorem is given which in certain circumstances allows the researcher to draw conclusions about the sign of the bias of unmeasured confounding. Specifically, it is possible to determine the sign of the bias when monotonicity relationships hold between the unmeasured confounding variable and the treatment, and between the unmeasured confounding variable and the outcome. Some discussion is given to the conditions under which the theorem applies and the strengths and limitations of using the theorem to assess the sign of the bias of unmeasured confounding.

Language: en