[Rasch] Intepreting Rasch-Andrich (or other ) thresholds in checklist scores (NOT likert scales)
mike at winsteps.com
Mon Mar 25 18:50:53 EST 2013
Thank you for your question, Imogene.
Your checklist is acting as a testlet of 12 locally-dependent items. The
testlet becomes a super-item with a "rating" equal to the score on the
David Andrich comments on this situation in
As always, the Rasch measures are interval measures, but the meaning of
the Rasch-Andrich thresholds depends on the degree of local dependency
among the criteria. If you want to divide up the latent variable
according to the count of correct criteria, then it would be easier for
your audience if you use the Rasch-Thurstone thresholds instead of the
Rasch-Andrich thresholds. See, for instance,
On 3/24/2013 20:04 PM, Imogene Rothnie wrote:
> I have a checklist type assessment where say ANY 9 correct criteria
> out of 12 would produce the same Rasch measure. This is opposed to
> the usual likert scale ratings of performance.
> I want to look at the Rasch-Andrich thresholds between checklist
> scores achieved on each station. Is it valid to view increasing N
> checklist items correct as interval measurement, or even in the way we
> would interpret Rasch-Andrich thresholds for a likert scale type item?
> Many thanks
> Imogene Rothnie
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