grm_iif: Item Information Function for GRM

In exametrika: Test Theory Analysis and Biclustering

Item Information Function for GRM

Description

Calculates the value of the Item Information Function for the Graded Response Model.

Usage

grm_iif(theta, a, b)

Arguments

theta	Latent trait value of the subject
a	Discrimination parameter of IRF
b	Vector of difficulty parameters (thresholds) of IRF

Value

Value of the Item Information Function

Examples

## Not run: 
# Example for an item with 3 categories
a <- 1.5
b <- c(-1.0, 1.0)
thetas <- seq(-3, 3, by = 0.1)
info <- sapply(thetas, function(t) grm_iif(t, a, b))
plot(thetas, info, type = "l", xlab = "Theta", ylab = "Information")

## End(Not run)

exametrika documentation built on Aug. 21, 2025, 5:27 p.m.