Activate paths opened by stratifying on a collider

Stratifying on colliders can open biasing pathways between variables. activate_collider_paths activates any such pathways given a variable or set of variables to adjust for and adds them to the tidy_dagitty.

Usage

activate_collider_paths(.tdy_dag, adjust_for, ...)

Arguments

.tdy_dag

input graph, an object of class tidy_dagitty or dagitty

adjust_for

a character vector, the variable(s) to adjust for.

...

additional arguments passed to tidy_dagitty()

Value

a tidy_dagitty with additional rows for collider-activated pathways

See also

control_for(), ggdag_adjust(), geom_dag_collider_edges()

Examples

dag <- dagify(m ~ x + y, x ~ y)

collided_dag <- activate_collider_paths(dag, adjust_for = "m")
collided_dag
#> # A DAG with 3 nodes and 3 edges
#> #
#> # Paths opened by conditioning on a collider: x <-> y, x <-> y
#> #
#> # A tibble: 6 × 9
#>   name        x      y direction to       xend   yend circular collider_line
#>   <chr>   <dbl>  <dbl> <fct>     <chr>   <dbl>  <dbl> <lgl>    <lgl>        
#> 1 m      0.0753 -0.401 NA        NA    NA      NA     FALSE    FALSE        
#> 2 x     -0.928  -0.405 ->        m      0.0753 -0.401 FALSE    FALSE        
#> 3 y     -0.430   0.466 ->        m      0.0753 -0.401 FALSE    FALSE        
#> 4 y     -0.430   0.466 ->        x     -0.928  -0.405 FALSE    FALSE        
#> 5 x     -0.928  -0.405 <->       y     -0.430   0.466 NA       TRUE         
#> 6 x     -0.928  -0.405 <->       y     -0.430   0.466 NA       TRUE