Plot the ATT(g,t) matrix from a Callaway-Sant'Anna event study

Visualises the full cohort-by-period ATT(g,t) matrix stored in the att_gt attribute of an es_result object produced by run_es(estimator = "cs"). Two display styles are available:

"heatmap": a tile plot with calendar time \(t\) on the x-axis and cohort \(g\) on the y-axis, colour-filled by the point estimate. Cells whose pointwise confidence interval excludes zero are marked with a filled dot; cells that are simultaneously significant (when bootstrap data are available) are additionally marked with an open diamond.
"facet": one panel per cohort showing ATT(g,t) over calendar time \(t\) with a pointwise confidence ribbon, mirroring the style of plot_es(). A lighter simultaneous CI ribbon is overlaid when bootstrap data are available.

Both types draw a vertical dashed line at \(t = g\) (treatment onset) for each cohort.

Usage

# S3 method for class 'att_gt_result'
plot(
  x,
  type = c("heatmap", "facet"),
  ci_level = 0.95,
  zero_line = TRUE,
  theme = c("bw", "minimal", "classic"),
  color = NULL,
  fill = NULL,
  alpha = NULL,
  ...
)

# S3 method for class 'att_gt_result'
autoplot(object, ...)

Arguments

x: An es_result object returned by run_es(estimator = "cs"), or an att_gt_result data frame produced by extracting attr(x, "att_gt") and giving it class "att_gt_result".
type: "heatmap" (default) or "facet".
ci_level: Confidence level for pointwise intervals (default 0.95).
zero_line: Logical; draw a horizontal reference line at zero in the "facet" display (default TRUE).
theme: One of "bw" (default), "minimal", or "classic".
color: Line and point colour used in the "facet" display (defaults to the package's steel blue, matching plot.es_result()).
fill: Ribbon fill colour in the "facet" display (defaults to the package's lighter ribbon tint).
alpha: Ribbon transparency in the "facet" display (default 0.35).
...: Passed on to the plotting engine.
object: An att_gt_result object; see att_gt().

Value

A ggplot2::ggplot() object.

Bootstrap annotation

When attr(x, "bootstrap") is present (i.e., run_es() was called with bootstrap = TRUE), both plot types add simultaneous inference overlays sourced from the (g,t)-level bootstrap object.

Examples

if (FALSE) { # \dontrun{
cs_result <- event_study(y ~ 1 | id + year, data = mydata, time = year,
                         timing = g, estimator = "cs")
plot(att_gt(cs_result))
plot(att_gt(cs_result), type = "facet")
} # }