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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, group = NULL)

Arguments

x

an object of class 'SingleGroupClass', or an object of class 'MultipleGroupClass' if a suitable group input were supplied
which.items

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

group argument to pass to extract.group function. Required when the input object is a multiple-group model

Author(s)

References

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

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

See Also

Examples

## Not run: 

mod <- mirt(Science, 2)
MDIFF(mod)

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


## End(Not run)
mirt

Multidimensional Item Response Theory

v1.33.2
GPL (>= 3)
Authors
Phil Chalmers [aut, cre] (<https://orcid.org/0000-0001-5332-2810>), Joshua Pritikin [ctb], Alexander Robitzsch [ctb], Mateusz Zoltak [ctb], KwonHyun Kim [ctb], Carl F. Falk [ctb], Adam Meade [ctb], Lennart Schneider [ctb], David King [ctb], Chen-Wei Liu [ctb], Ogreden Oguzhan [ctb]
Initial release

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