[Rasch] Anchoring Question

Kathleen Parkinson kparki2 at uic.edu
Sun Sep 27 09:42:08 AEST 2015


Hello--

In regard to my anchor question, I realize I just applied a pivot, not an
item anchor.  Researching this further, it appears I would need at least 5
items to obtain precise estimates.  Is it ever possible to anchor the items
when there are only 2?  My sample size is N=122.

Thanks again,

Kathleen

On Sat, Sep 26, 2015 at 6:07 PM, Kathleen Parkinson <kparki2 at uic.edu> wrote:

> Hello,
>
> I am trying to anchor pre-test and post-test scores for an early language
> learning test with only 2 items.  I've used the pivot anchoring procedure,
> using the category structure measures to link the tests, but this is
> throwing off my person measures (my person for the anchored pretest
> measures are starting from point 0 to 45 while my post-test measures are
> ranging from -18 to 20.  Winsteps example2 shows the anchoring procedure
> with units, how are the units determine?  I'll appreciate anyone's advice
> on how to anchor pretest to post-test scores.  Here's my control file fyi:
>
> Thanks!
>
> Kathleen
>
> --
> Kathleen Parkinson
> Research Analyst
> Center for Urban Education Leadership
> University of Illinois at Chicago
>



-- 
Kathleen Parkinson
Research Analyst
Center for Urban Education Leadership
University of Illinois at Chicago
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