Functionalities of the dagR package for directed acyclic graphs

Background: Directed acyclic graphs (DAGs) have in recent years been introduced to the field of epidemiology. They present a valuable framework for understanding causality and confounding, but their use still remains limited. Here, I present the add-on package dagR, a set of basic DAG-related functions for the statistical software R. Materials. Examples of DAGs created, evaluated, and drawn using dagR are presented. dagR follows the graphical algorithms described in the DAG literature in order to find biasing paths or associations introduced by adjustment. Convenient functions can be used to identify minimal suf…