Plot Contamination Weights as a Tile Heatmap

Creates a ggplot2 tile heatmap of the contamination weights returned by compute_contamination_weights().

Each cell at position (twfe_period, catt_label) shows the weight \(\omega^{\ell''}_{e,\ell}\): how much of \(CATT_{e,\ell}\) leaks into the TWFE coefficient \(\hat\mu_{\ell''}\).

Diagonal cells (catt_period == twfe_period): own-period weights (sum across cohorts should be \(\approx 1\)).
Off-diagonal cells: cross-period contamination (ideally close to zero under treatment effect homogeneity).

Usage

plot_contamination_weights(
  x,
  limit_abs = NULL,
  midpoint = 0,
  low = "#2166AC",
  mid = "white",
  high = "#B2182B",
  theme = c("bw", "minimal", "classic"),
  show_values = FALSE,
  value_digits = 2L
)

Arguments

x: An sa_contamination_weights object from compute_contamination_weights().
limit_abs: Numeric; symmetric colour scale limit [-limit, limit]. Defaults to the maximum absolute weight (rounded up to one decimal).
midpoint: Numeric; midpoint of the diverging colour scale (default 0).
low: Colour for negative weights (default "#2166AC").
mid: Colour for zero weight (default "white").
high: Colour for positive weights (default "#B2182B").
theme: Character; "bw" (default), "minimal", or "classic".
show_values: Logical; overlay weight values in each tile (default FALSE).
value_digits: Integer; decimal digits when show_values = TRUE (default 2L).

Value

A ggplot2::ggplot() object.

Usage

Arguments

Value

See also