plotIIF: Plot item information functions (IIFs)

In secastroal/GGUM: Generalized Graded Unfolding Model

Plot item information functions (IIFs)

Description

plot.IIF plots the IIFs for the GUM and the GGUM.

Usage

plotIIF(IP, Th, items = NULL, quiet = FALSE)

Arguments

IP	Object of class GGUM.
Th	Theta estimates from function Theta.EAP().
items	Vector indicating the items for which the ICCs are to be plotted. Default is all items.
quiet	Render all plots for items at once? Default is FALSE.

Value

The function returns the (x, y) coordinates of the IIFs.

Details

This function plots the item information functions (IIFs).

Author(s)

Jorge N. Tendeiro, [e-mail]

Examples

## Not run: 
# For GUM:
# Generate data
#   (toy example: Too few items (due to computation time constraints) for 
#   accurate estimation of person parameters; larger number of items is 
#   required in practice):
gen1 <- GenData.GGUM(400, 5, 3, "GUM", seed = 139)
# Fit the GUM:
fit1 <- GUM(gen1$data, 3)
th1  <- Theta.EAP(fit1)
# Plot IIFs:
plotIIF(fit1, th1, items = 1, quiet = TRUE)

## End(Not run)
## Not run: 
# For GGUM:
# Generate data:
set.seed(1); C <- sample(3:5, 10, replace = TRUE)
gen2 <- GenData.GGUM(2000, 10, C, "GGUM", seed = 156)
# Fit the GGUM:
fit2 <- GGUM(gen2$data, C)
th2  <- Theta.EAP(fit2)
# Plot IIFs:
plotIIF(fit2, th2, items = 1, quiet = TRUE)

## End(Not run)

secastroal/GGUM documentation built on Feb. 21, 2023, 3:39 p.m.