plot.PanelMatch function

Plot the distribution of the sizes of matched sets.

A plot method for creating a histogram of the distribution of the sizes of matched sets. This method accepts all standard optional hist arguments via the ... argument. By default, empty matched sets (treated units that could not be matched with any control units) are noted as a vertical bar at x = 0 and not included in the regular histogram. See the include.empty.sets argument for more information about this. If the quantity of interest is ATE, a plot will be returned for the matched sets associated with the att and the atc.

## S3 method for class 'PanelMatch'
plot(
  x,
  ...,
  border = NA,
  col = "grey",
  ylab = "Frequency of Size",
  xlab = "Matched Set Size",
  lwd = NULL,
  main = "Distribution of Matched Set Sizes",
  freq = TRUE,
  include.empty.sets = FALSE
)

Arguments

• x: a PanelMatch object
• ...: optional arguments to be passed to hist()
• border: default is NA. This is the same argument as the standard argument for hist()
• col: default is "grey". This is the same argument as the standard argument for hist()
• ylab: default is "Frequency of Size". This is the same argument as the standard argument for hist()
• xlab: default is "Matched Set Size". This is the same argument as the standard argument for hist()
• lwd: default is NULL. This is the same argument as the standard argument for hist()
• main: default is "Distribution of Matched Set Sizes". This is the same argument as the standard argument for hist
• freq: default is TRUE. See freq argument in hist() function for more.
• include.empty.sets: logical value indicating whether or not empty sets should be included in the histogram. default is FALSE. If FALSE, then empty sets will be noted as a separate vertical bar at x = 0. If TRUE, empty sets will be included as normal sets.

Examples

dem.sub <- dem[dem[, "wbcode2"] <= 100, ]
dem.sub.panel <- PanelData(dem.sub, "wbcode2", "year", "dem", "y")
PM.results <- PanelMatch(panel.data = dem.sub.panel,
                         lag = 4, 
                         refinement.method = "mahalanobis",
                         match.missing = TRUE,
                         covs.formula = ~ I(lag(tradewb, 1:4)) + I(lag(y, 1:4)),
                         size.match = 5, qoi = "att",
                         lead = 0:4, forbid.treatment.reversal = FALSE)
plot(PM.results)
plot(PM.results, include.empty.sets = TRUE)