itemDist: Item difficulty distribution

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

Item difficulty distribution

Description

This function requires a fitted mirt-model of class SingleGroupClass to visualize item difficulty distribution. Currently only works for unidimensional models.

Usage

itemDist(model, theta_range = c(-4, 4), ...)

Arguments

model	an object of class SingleGroupClass returned by the function mirt().
...	any argument passed to geom_point()

Value

a ggplot object.

Examples

# Loading packages
library(mirt)
library(ggmirt)

# Getting data
data <- expand.table(LSAT7)

# Fitting a model 
(mod <- mirt(data, 1))

# Simple plot
itemDist(mod)

# Customized plot
itemDist(mod, size = 3, shape = 17, color = "blue")

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