Compute multidimensional difficulty index

Description

Returns a matrix containing the MDIFF values (Reckase, 2009). Only suppored for items of class 'dich' and 'graded'. Note that the logistic intercept parameters are divided by 1.702 to match the normal ogive metric.

Usage

MDIFF(x, which.items = NULL)

Arguments

Author(s)

Phil Chalmers rphilip.chalmers@gmail.com

References

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

See Also

extract.group, MDISC

Examples

## Not run: 

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


## End(Not run)

Results