backDoorGraph {dagitty}

Back-Door Graph

Description

Removes every first edge on a proper causal path from x. If x is a MAG or PAG, then only “visible” directed edges are removed (Zhang, 2008).

Usage

backDoorGraph(x)

Arguments

x

the input graph, a DAG, MAG, PDAG, or PAG.

References

J. Zhang (2008), Causal Reasoning with Ancestral Graphs. Journal of Machine Learning Research 9: 1437-1474.

Examples

g <- dagitty( "dag { x <-> m <-> y <- x }" )
backDoorGraph( g ) # x->y edge is removed

g <- dagitty( "mag { x <-> m <-> y <- x }" )
backDoorGraph( g ) # x->y edge is not removed

g <- dagitty( "mag { x <-> m <-> y <- x <- i }" )
backDoorGraph( g ) # x->y edge is removed