Degradation surface figure — plot_degradation

Produces a 3-panel figure showing estimator bias under simultaneous instrument exogeneity violations. Panels: (A) IV2SLS2 NDE bias surface, (B) PGC2Gm NDE bias surface, (C) crossover map showing which estimator has lower |NDE bias| at each grid cell.

Usage

plot_degradation_surface(
  results,
  rho_G1_grid = c(0, 0.1, 0.2, 0.3, 0.5),
  rho_G2_grid = c(0, 0.1, 0.2, 0.3, 0.5),
  omega_facet = TRUE,
  file = NULL,
  width = 15,
  height = 5.5
)

Arguments

results: Data frame with columns rho_G1, rho_G2, method, NDE_bias, NIE_bias, and derived NDE_abs, NIE_abs. Typically built by sweeping sweep_mediation_param() across a rho_G1 x rho_G2 grid.
rho_G1_grid: Numeric vector of exposure-instrument violation values.
rho_G2_grid: Numeric vector of mediator-instrument violation values.
omega_facet: Logical: when the sensitivity surface swept omega_1 / omega_2 (more than one distinct value), facet the rho_G1 x rho_G2 heatmaps by the omega cell. Default TRUE. Ignored when omega was not swept.
file: Optional file path to save the figure.
width: Figure width in inches.
height: Figure height in inches.

Value

A patchwork ggplot object.

Examples

results <- expand.grid(rho_G1 = c(0, 0.2), rho_G2 = c(0, 0.2),
  method = c("IV2SLS2", "PGC2Gm"))
results$NDE_bias <- rnorm(nrow(results), 0, 0.05)
results$NIE_bias <- rnorm(nrow(results), 0, 0.05)
plot_degradation_surface(results, rho_G1_grid = c(0, 0.2),
  rho_G2_grid = c(0, 0.2))