R script demonstrating how to plot rootograms in R

rootograms.R

library(vcd)
library(patchwork)

set.seed(123)

# we make 4 independent draws from a poisson
# distribution, fit the poisson distribution
# and then draw the rootogram to compare observed
# and fitted values.
plots <- lapply(1:4, function(draw) {
  counts <- rpois(100, 1)
  fit <- vcd::goodfit(counts, type = "poisson", method = "ML")
  suppressWarnings(
    vcd::rootogram(fit, scale = "raw", main = sprintf("Draw %s", draw),
                   return_grob = TRUE
    )
  )
})
patchwork::wrap_plots(plots)