[R] DIF

[Achim Zeileis]

On Tue, 9 Dec 2014, Richard M. Heiberger wrote:

> I recommend the likert() function in the HH package.
>
> install.packages("HH")
> library(HH)
> ?likert

I think this only visualizes the polytomous items but provides no formal 
inference for IRT modeling and DIF testing.

For fitting polytomous IRT models (PCM, RSM, etc.) there are various R 
packages available, probably most prominently the "eRm" package. This also 
includes several tests for DIF. But many other approaches are also 
available (including the "lordif" package). A good first overview is given 
in the Psychometrics task view on CRAN, see: 
http://CRAN.R-project.org/view=Psychometrics

hth,
Z

>
>
> On Tue, Dec 9, 2014 at 3:22 AM, munevver kaya <munevver.rock at gmail.com> wrote:
>> Hello,
>> I will analyze polytomous differential item functioning for IRT. I have a
>> Likert type scale. For example, I want to analyze items in term of gender.
>> Is lordifsufficient for this or are there any other packages in R
>> programme?
>> Best Regards,
>>
>>         [[alternative HTML version deleted]]
>>
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> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>