draw.rootogram: Draw a rootogram

In gavinsimpson/gratia: Graceful 'ggplot'-Based Graphics and Other Functions for GAMs Fitted Using 'mgcv'

Draw a rootogram

Description

A rootogram is a model diagnostic tool that assesses the goodness of fit of a statistical model. The observed values of the response are compared with those expected from the fitted model. For discrete, count responses, the frequency of each count (0, 1, 2, etc) in the observed data and expected from the conditional distribution of the response implied by the model are compared. For continuous variables, the observed and expected frequencies are obtained by grouping the data into bins. The rootogram is drawn using ggplot2::ggplot() graphics. The design closely follows Kleiber & Zeileis (2016).

Usage

## S3 method for class 'rootogram'
draw(
  object,
  type = c("hanging", "standing", "suspended"),
  sqrt = TRUE,
  ref_line = TRUE,
  warn_limits = TRUE,
  fitted_colour = "steelblue",
  bar_colour = NA,
  bar_fill = "grey",
  ref_line_colour = "black",
  warn_line_colour = "black",
  ylab = NULL,
  xlab = NULL,
  ...
)

Arguments

object	and R object to plot.
type	character; the type of rootogram to draw.
sqrt	logical; show the observed and fitted frequencies
ref_line	logical; draw a reference line at zero?
warn_limits	logical; draw Tukey's warning limit lines at +/- 1?
fitted_colour, bar_colour, bar_fill, ref_line_colour, warn_line_colour	colours used to draw the respective element of the rootogram.
xlab, ylab	character; labels for the x and y axis of the rootogram. May be missing (NULL), in which case suitable labels will be used. '
...	arguments passed to other methods.

Value

A 'ggplot' object.

References

Kleiber, C., Zeileis, A., (2016) Visualizing Count Data Regressions Using Rootograms. Am. Stat. 70, 296–303. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1080/00031305.2016.1173590")}

See Also

rootogram() to compute the data for the rootogram.

Examples

load_mgcv()
df <- data_sim("eg1", n = 1000, dist = "poisson", scale = 0.1, seed = 6)

# A poisson example
m <- gam(y ~ s(x0, bs = "cr") + s(x1, bs = "cr") + s(x2, bs = "cr") +
  s(x3, bs = "cr"), family = poisson(), data = df, method = "REML")
rg <- rootogram(m)

# plot the rootogram
draw(rg)

# change the type of rootogram
draw(rg, type = "suspended")

gavinsimpson/gratia documentation built on April 24, 2024, 6:29 a.m.