title: Sensitivity plots for confounder bias in the single mediator model.
abstract: BACKGROUND
  Causal inference continues to be a critical aspect of evaluation research. Recent research in causal inference for statistical mediation has focused on addressing the sequential ignorability assumption; specifically, that there is no confounding between the mediator and the outcome variable.
  
  
  OBJECTIVE
  This article compares and contrasts three different methods for assessing sensitivity to confounding and describes the graphical depiction of these methods.
  
  
  METHODS
  Two types of data were used to fully examine the plots for sensitivity analysis. The first type was generated data from a single mediator model with a confounder influencing both the mediator and the outcome variable. The second was data from an actual intervention study. With both types of data, situations are examined where confounding has a large effect and a small effect.
  
  
  METHODS
  The nonsimulated data were from a large intervention study to decrease intentions to use steroids among high school football players. We demonstrate one situation where confounding is likely and another situation where confounding is unlikely.
  
  
  CONCLUSIONS
  We discuss how these methods could be implemented in future mediation studies as well as the limitations and future directions for these methods.
authors.affiliation: Department of Behavioral Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Cox
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Kisbu-Sakarya
authors.forename: Milica
authors.initials: M
authors.lastname: Miočević
authors.forename: David P
authors.initials: DP
authors.lastname: MacKinnon
mesh_terms: D015982:Bias; D015986:Confounding Factors, Epidemiologic; D005069:Evaluation Studies as Topic; D006801:Humans; D016014:Linear Models; D015233:Models, Statistical
keywords: causal inference; confounder bias; indirect effects; mediation; sensitivity analysis