psychotree (version 0.12-2)

DIFSim: Artificial Data with Differential Item Functioning

Description

Artificial data simulated from a Rasch model where the items exhibit differential item functioning (DIF).

Usage

data("DIFSim")

encoding

latin1

Details

The data are employed for illustration in Strobl et al. (2010), whose results are replicated on the manual page for raschtree.

References

Strobl, C., Kopf, J., and Zeileis, A. (2010). A New Method for Detecting Differential Item Functioning in the Rasch Model. Technical Report 92. Department of Statistics, Ludwig-Maximilians-Universit�t M�nchen. http://epub.ub.uni-muenchen.de/11915/

See Also

raschtree

Examples

## data
data("DIFSim", package = "psychotree")

## summary of covariates
summary(DIFSim[,-1])

## histogram of raw scores
hist(rowSums(DIFSim$resp), breaks = 0:19 + 0.5)