DIFlasso (version 1.0-4)

refitDIFlasso: Refit Function for DIFlasso

Description

Performs the refit of a DIFlasso object. Only the items diagosed as DIF items will be used to perform a new fit of the final model.

Usage

refitDIFlasso(dif.obj)

Value

theta

Estimated person abilities after refit

beta

Estimated item difficulties after refit

gamma

Estimated item-specific parameters after refit; one row per covariate, one column per item

P

Number of persons

I

Number of items

m

Number of covariates

ref.item

Reference item

dif.items

Which items have been detected to be DIF items?

names.y

Names of the items

names.x

Names of the covariates

Arguments

dif.obj

DIFlasso object, created by DIFlasso

Author

Gunther Schauberger

https://www.sg.tum.de/epidemiologie/team/schauberger/

References

Tutz, Gerhard and Schauberger, Gunther (2015): A Penalty Approach to Differential Item Functioning in Rasch Models, Psychometrika, 80(1), 21 - 43

See Also

print.DIFlasso.refit, plot.DIFlasso.refit, DIFlasso

Examples

if (FALSE) {
data(simul.data)

Y <- simul.data[,1:10]
X <- simul.data[,11:13]

m1 <- DIFlasso(Y = Y, X = X, trace = TRUE) 
print(m1)
plot(m1)

m2 <- refitDIFlasso(m1)
print(m2)
plot(m2)
}