itempersonMap: Visualize item person map and scale properties based on Rasch...

In masurp/ggmirt: Plotting functions to extend "mirt" for IRT analyses

Visualize item person map and scale properties based on Rasch model

Description

This function takes a fitted mirt-model and visualizes and plots item-person-map (also known as Kernel-Density Plots or Wright maps) on the left, and add a scale characteristic curve, scale information curve, and a marginal reliability curve on the right.

Usage

itempersonMap(
  model,
  theta_range = c(-4, 4),
  title = "Item Person Map",
  margin = c(1, 0, -1.5, 0),
  density = FALSE,
  color = "red",
  shape = 17,
  size = 3,
  theme = theme_minimal(),
  ...
)

Arguments

model	an object of class SingleGroupClass returned by the function mirt().
title	title for the plot (defaults to "Item-Person-Map")
margin	margins around the top figure. Sometimes one might want to adjust this.
density	logical value indicating whether a smoothed density curve or a standard histogram should be plotted.
color	color of the geoms, defaults to "red".
shape	can be used to change the shape of the geom, defaults to triangles (17).
size	size of the geom, default to 3.
theme	any ggplot theme.
...	any argument passed to geom_point().
limits	range to be shown on the x-axis

Value

a plot grid as returned by cowplot::plot_grid()

Examples

library(mirt)
library(ggmirt)
data <- expand.table(LSAT7)
(mod <- mirt(data, 1))

itempersonMap(mod)

masurp/ggmirt documentation built on Oct. 14, 2023, 1:16 p.m.