scaleCharPlot: Scale Characteristic Curve

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

Scale Characteristic Curve

Description

Once model-based theta score estimates are computed, it often is of interest to transform those estimates into the original scale metric. A scale characteristic function provides a means of transforming estimated theta scores to expected true scores in the original scale metric. This transformation back into the original scale metric provides a more familiar frame of reference for interpreting scores. This function provides a visualization for this transformation.

Usage

scaleCharPlot(
  model,
  theta_range = c(-4, 4),
  color = "red",
  title = "Scale Characteristic Curve"
)

Arguments

model	an object of class SingleGroupClass returned by the function mirt().
theta_range	range to be shown on the x-axis
color	color of the line
title	title for the plot (defaults to "Person Infit and Outfit Statistics")

Value

a ggplot

Examples

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

scaleCharPlot(mod)

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