Using instrumental variables to address unmeasured confounding in causal mediation analysis.
Biometrics
; 80(1)2024 Jan 29.
Article
in En
| MEDLINE
| ID: mdl-38412300
ABSTRACT
Mediation analysis is a strategy for understanding the mechanisms by which interventions affect later outcomes. However, unobserved confounding concerns may be compounded in mediation analyses, as there may be unobserved exposure-outcome, exposure-mediator, and mediator-outcome confounders. Instrumental variables (IVs) are a popular identification strategy in the presence of unobserved confounding. However, in contrast to the rich literature on the use of IV methods to identify and estimate a total effect of a non-randomized exposure, there has been almost no research into using IV as an identification strategy to identify mediational indirect effects. In response, we define and nonparametrically identify novel estimands-double complier interventional direct and indirect effects-when 2, possibly related, IVs are available, one for the exposure and another for the mediator. We propose nonparametric, robust, efficient estimators for these effects and apply them to a housing voucher experiment.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Mediation Analysis
Language:
En
Journal:
Biometrics
Year:
2024
Document type:
Article
Affiliation country:
United States
Country of publication:
United kingdom