mirt (version 1.27.1)

MDIFF: Compute multidimensional difficulty index

Description

Returns a matrix containing the MDIFF values (Reckase, 2009). Only supported for items of class 'dich' and 'graded'.

Usage

MDIFF(x, which.items = NULL)

Arguments

x

an object of class 'SingleGroupClass'

which.items

a vector indicating which items to select. If NULL is used (the default) then MDISC will be computed for all items

References

Chalmers, R., P. (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29. 10.18637/jss.v048.i06

Reckase, M. D. (2009). Multidimensional Item Response Theory. Springer.

See Also

extract.group, MDISC

Examples

# NOT RUN {
mod <- mirt(Science, 2)
MDIFF(mod)

mod <- mirt(expand.table(LSAT7), 2)
MDIFF(mod)

# }