node_regionplot: Panel-Generating Function for Visualizing IRT Tree Models
In psychotree: Recursive Partitioning Based on Psychometric Models

node_regionplot

R Documentation

Panel-Generating Function for Visualizing IRT Tree Models

Description

Panel-generating function for visualizing the regions of expected item responses across abilities (via shaded rectangles) based on the parameters from the nodes in IRT tree models.

Usage

node_regionplot(
  mobobj,
  names = FALSE,
  abbreviate = TRUE,
  type = c("mode", "median", "mean"),
  ref = NULL,
  ylim = NULL,
  off = 0.1,
  col_fun = gray.colors,
  bg = "white",
  uo_show = TRUE,
  uo_col = "red",
  uo_lty = 2,
  uo_lwd = 1.25,
  ylines = 2
)

Arguments

`mobobj`	an object of class `"npltree"` or class `"mob"` fitted by `npltree`
`names`	logical or character. If `TRUE`, the names of the items are displayed on the x-axis. If `FALSE`, numbers of items are shown. Alternatively a character vector of the same length as the number of items can be supplied.
`abbreviate`	logical. Should item names be abbreviated? If numeric this controls the length of the abbreviation.
`type`	character, specifying which type of threshold parameters are to be used to mark the category regions per item in the plot (see `regionplot` for details).
`ref`	a vector of labels or position indices of item parameters which should be used as restriction/for normalization. If `NULL` (the default), all items are used (sum zero restriction). See `threshpar` for more details.
`ylim`	y axis limits
`off`	numeric, the distance (in scale units) between two item rectangles.
`col_fun`	function. Function to use for creating the color palettes for the rectangles. Per default `gray.colors` is used. Be aware that `col_fun` should accept as first argument an integer specifying the number of colors to create.
`bg`	color for background filling.
`uo_show`	logical. If set to `TRUE` (the default), disordered absolute item threshold parameters are indicated by a horizontal line (only if `type` is set to `"mode"`).
`uo_col`	character, color of indication lines (if `uo_show`).
`uo_lty`	numeric. Line typ of indication lines (if `uo_show`).
`uo_lwd`	numeric. Line width of indication lines (if `uo_show`).
`ylines`	numeric. Number of lines used for y-axis labels.