Plot Item Characteristic Curves (ICCs)

An ICC shows the probability of getting an item correct as a function of ability. Each item gets one curve. Harder items have curves shifted to the right.

Usage

plot_icc(object, items = NULL, theta_range = c(-4, 4), ci = TRUE, ...)

Arguments

object

A birt_fit object.

items

Which items to plot (integer vector). Default: all.

theta_range

Range of ability values to show. Default c(-4, 4).

ci

Show 95% credible bands? Default TRUE.

...

Ignored.

Value

A ggplot2 object.