dLR: Dimensionality test for the multidimensional polytomous Rasch...

In pcIRT: IRT Models for Polytomous and Continuous Item Responses

Description

This function tests whether the multidimensional polytomous Rasch model can be reduced to a unidimensional polytomous model.

Usage

dLRT(MPRMobj)

## S3 method for class 'dLR'
print(x, ...)

## S3 method for class 'dLR'
summary(object, ...)

Arguments

MPRMobj	Object of class MPRM
x	object of class dLR
...	...
object	object of class dLR

Details

For this test, a unidimensional model assuming the categories as linearly dependent is computed. Subsequently a Likelihood Ratio test is conducted.

Value

emp_Chi2	χ^2 distributed value of the Likelihood Ratio test
df	degrees of freedom of the test statistic
pval	p value of the test statistic

Author(s)

Christine Hohensinn

References

Fischer, G. H. (1974). Einfuehrung in die Theorie psychologischer Tests [Introduction to test theory]. Bern: Huber.

See Also

MPRM LRT

Examples

#simulate data set
simdat <- simMPRM(rbind(matrix(c(-1.5,0.5,0.5,1,0.8,-0.3, 0.2,-1.2), 
   ncol=4),0), 500)

#estimate MPRM item parameters
res_mprm <- MPRM(simdat$datmat)

res_dlrt <- dLRT(res_mprm)
summary(res_dlrt)

pcIRT documentation built on July 16, 2019, 1:02 a.m.