Directed acyclic graph (DAG) representing conditional independencies (by the absence of arrows) between the genetic instrument <i>Z</i>, the risk factor <i>X</i>, the outcome <i>Y</i> and the confounders <i>U</i>.

<p>Directed acyclic graph (DAG) representing conditional independencies (by the absence of arrows) between the genetic instrument <i>Z</i>, the risk factor <i>X</i>, the outcome <i>Y</i> and the confounders <i>U</i>.