itemfitPlot: Plotting itemfit estimates

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

Plotting itemfit estimates

Description

This function takes a fitted mirt-model and visualizes item infit and outfit estimates. The function builds on mirt::itemfit(). Currently only supported fact_stats = "infit".

Usage

itemfitPlot(
  model,
  fit_stats = "infit",
  color = "red",
  shape = 17,
  title = "Item Infit and Outfit Statistics",
  ...
)

Arguments

model	an object of class SingleGroupClass returned by the function mirt().
fit_stats	a character vector indicating which fit statistics should be computed. See mirt::infit() for supported inputs.
color	color of the item points.
shape	shape of the item points
title	title for the plot (defaults to "Item Infit and Outfit Statistics")

Value

a ggplot

References

• Linacre JM. (2002). What do Infit and Outfit, Mean-square and Standardized mean? Rasch Measurement Transactions, 16(2), p.878. https://www.rasch.org/rmt/rmt162f.htm

Examples

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

itemfitPlot(mod, fit_stats = "infit")

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