Quickly create a DAGs with common structures of bias — Quick Plots for Common DAGs • ggdag

base functions create an object of class dagitty; ggdag_* functions are wrappers that also call ggdag() on the dagitty object.

Usage

m_bias(
  x = NULL,
  y = NULL,
  a = NULL,
  b = NULL,
  m = NULL,
  x_y_associated = FALSE
)

butterfly_bias(
  x = NULL,
  y = NULL,
  a = NULL,
  b = NULL,
  m = NULL,
  x_y_associated = FALSE
)

confounder_triangle(x = NULL, y = NULL, z = NULL, x_y_associated = FALSE)

collider_triangle(x = NULL, y = NULL, m = NULL, x_y_associated = FALSE)

mediation_triangle(x = NULL, y = NULL, m = NULL, x_y_associated = FALSE)

quartet_collider(x = NULL, y = NULL, z = NULL, x_y_associated = TRUE)

quartet_confounder(x = NULL, y = NULL, z = NULL, x_y_associated = TRUE)

quartet_mediator(x = NULL, y = NULL, z = NULL, x_y_associated = FALSE)

quartet_m_bias(
  x = NULL,
  y = NULL,
  z = NULL,
  u1 = NULL,
  u2 = NULL,
  x_y_associated = TRUE
)

quartet_time_collider(
  x0 = NULL,
  x1 = NULL,
  x2 = NULL,
  x3 = NULL,
  y1 = NULL,
  y2 = NULL,
  y3 = NULL,
  z1 = NULL,
  z2 = NULL,
  z3 = NULL
)

ggdag_m_bias(
  x = NULL,
  y = NULL,
  a = NULL,
  b = NULL,
  m = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL,
  node = deprecated(),
  stylized = deprecated()
)

ggdag_butterfly_bias(
  x = NULL,
  y = NULL,
  a = NULL,
  b = NULL,
  m = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL,
  node = deprecated(),
  stylized = deprecated()
)

ggdag_confounder_triangle(
  x = NULL,
  y = NULL,
  z = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL,
  node = deprecated(),
  stylized = deprecated()
)

ggdag_collider_triangle(
  x = NULL,
  y = NULL,
  m = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL,
  node = deprecated(),
  stylized = deprecated()
)

ggdag_mediation_triangle(
  x = NULL,
  y = NULL,
  m = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL,
  node = deprecated(),
  stylized = deprecated()
)

ggdag_quartet_collider(
  x = NULL,
  y = NULL,
  z = NULL,
  x_y_associated = TRUE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL
)

ggdag_quartet_confounder(
  x = NULL,
  y = NULL,
  z = NULL,
  x_y_associated = TRUE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL
)

ggdag_quartet_mediator(
  x = NULL,
  y = NULL,
  z = NULL,
  x_y_associated = FALSE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL
)

ggdag_quartet_m_bias(
  x = NULL,
  y = NULL,
  z = NULL,
  u1 = NULL,
  u2 = NULL,
  x_y_associated = TRUE,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL
)

ggdag_quartet_time_collider(
  x0 = NULL,
  x1 = NULL,
  x2 = NULL,
  x3 = NULL,
  y1 = NULL,
  y2 = NULL,
  y3 = NULL,
  z1 = NULL,
  z2 = NULL,
  z3 = NULL,
  size = 1,
  edge_type = "link_arc",
  node_size = 16,
  text_size = 3.88,
  label_size = text_size,
  text_col = "white",
  label_col = "black",
  edge_width = 0.6,
  edge_cap = 8,
  arrow_length = 5,
  use_edges = TRUE,
  use_nodes = TRUE,
  use_stylized = FALSE,
  use_text = TRUE,
  use_labels = FALSE,
  label_geom = geom_dag_label_repel,
  text = NULL,
  label = NULL
)

Arguments

x, y, a, b, m, z: Character vector. Optional label. Default is NULL
x_y_associated: Logical. Are x and y associated? Default is FALSE.
u1, u2: Character vector. Optional label for unmeasured nodes, used in quartet_m_bias(). Default is NULL
x0, x1, x2, x3, y1, y2, y3, z1, z2, z3: Character vector. Optional labels for time-indexed nodes, used in quartet_time_collider(). Default is NULL
size: A numeric value scaling the size of all elements in the DAG. This allows you to change the scale of the DAG without changing the proportions.
edge_type: The type of edge, one of "link_arc", "link", "arc", "diagonal".
node_size: The size of the nodes.
text_size: The size of the text.
label_size: The size of the labels.
text_col: The color of the text.
label_col: The color of the labels.
edge_width: The width of the edges.
edge_cap: The size of edge caps (the distance between the arrowheads and the node borders).
arrow_length: The length of arrows on edges.
use_edges: A logical value. Include a geom_dag_edges*() function? If TRUE, which is determined by edge_type.
use_nodes: A logical value. Include geom_dag_point()?
use_stylized: A logical value. Include geom_dag_node()?
use_text: A logical value. Include geom_dag_text()?
use_labels: A logical value. Include a label geom? The specific geom used is controlled by label_geom.
label_geom: A geom function to use for drawing labels when use_labels = TRUE. Default is geom_dag_label_repel. Other options include geom_dag_label, geom_dag_text_repel, geom_dag_label_repel2, and geom_dag_text_repel2.
text: The bare name of a column to use for geom_dag_text(). If use_text = TRUE, the default is to use name.
label: The bare name of a column to use for labels. If use_labels = TRUE, the default is to use label.
node: Deprecated.
stylized: Deprecated.

Value

a DAG of class dagitty or a ggplot

Details

The quartet_* functions create DAGs that represent the causal quartet, which are four example datasets with identical statistical properties but different causal structures. These are inspired by Anscombe's quartet and demonstrate that statistical summaries alone cannot determine causal relationships. See Causal Inference in R

The four structures represent different relationships between exposure (x), outcome (y), and a covariate (z):

Collider: z is caused by both x and y (should not adjust for z)
Confounder: z causes both x and y (must adjust for z)
Mediator: z is on the causal path from x to y (adjust for direct effect only)
M-bias: z is a collider with unmeasured confounders u1 and u2 (should not adjust for z)

The time-varying collider (quartet_time_collider()) demonstrates how time-ordering can help identify causal relationships when variables are measured at multiple time points.

References

D'Agostino McGowan L, Gerke T, Barrett M (2023). "Causal inference is not just a statistics problem." Journal of Statistics and Data Science Education, 32(1), 1-4. doi:10.1080/26939169.2023.2276446

Examples

m_bias() |> ggdag_adjust("m")

ggdag_confounder_triangle()


# Causal Quartets
ggdag_quartet_collider()

ggdag_quartet_confounder()

ggdag_quartet_mediator()

ggdag_quartet_m_bias()


# Time-varying collider
ggdag_quartet_time_collider()