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Test DAG properties

Source: R/is_functions.R
is_dag_properties.Rd

These functions test various properties of DAGs:

  • is_acyclic() tests whether a DAG is acyclic

  • is_adjustment_set() tests whether a set of variables is a valid adjustment set

  • is_d_separated() tests whether two sets of variables are d-separated

  • is_d_connected() tests whether two sets of variables are d-connected

Usage

is_acyclic(.dag)

is_adjustment_set(.dag, Z, exposure = NULL, outcome = NULL)

is_d_separated(.dag, from = NULL, to = NULL, controlling_for = NULL)

is_d_connected(.dag, from = NULL, to = NULL, controlling_for = NULL)

Arguments

.dag

A tidy_dagitty or dagitty object

Z

A set of variables to test or condition on. This can be a character vector of variable names, a list of the form list(c(...)), or NULL.

exposure

A character vector, the exposure variable. Default is NULL, in which case it will be determined from the DAG.

outcome

A character vector, the outcome variable. Default is NULL, in which case it will be determined from the DAG.

from

A character vector with starting node name(s), or NULL. If NULL, checks DAG for exposure variable.

to

A character vector with ending node name(s), or NULL. If NULL, checks DAG for outcome variable.

controlling_for

A set of variables to control for. This can be a character vector of variable names, a list of the form list(c(...)), or NULL. When NULL, no control is applied. Default is NULL.

Value

A logical value indicating whether the tested property holds

Examples

dag <- dagify(
  y ~ x + z,
  x ~ z,
  exposure = "x",
  outcome = "y"
)

is_acyclic(dag)
#> [1] TRUE
is_adjustment_set(dag, "z")
#> [1] TRUE
is_d_separated(dag, "x", "y", "z")
#> [1] FALSE
is_d_connected(dag, "x", "y")
#> [1] TRUE