clr_tests: Conditional Likelihood Ratio Tests (CLR)
Description
The conditional likelihood ratio tests compare item parameters in low and high score groups
for an overall test of homogeneity, and in groups defined by the levels of exogenous factors
for tests of no differential item functioning (DIF).
Usage
clr_tests(dat.items, dat.exo = NULL, model = c("RM", "PCM"))
Value
matrix with test statistics, df and p values.
Arguments
dat.items
A data frame with the responses to the items.
dat.exo
A single factor or a data frame consisting of one or more exogenous factor variables.
model
If model="RM" a Rasch model will be fitted,
if model="PCM" a partial credit model for polytomous items is used.
Author
Marianne Mueller
References
Andersen, E.B. (1973). A goodness of fit test for the Rasch model. Psychometrika, 38, 123-140.