[Rasch] Rasch S.E at the cut score...reciprocal?

Imogene Rothnie imogene.rothnie at sydney.edu.au
Fri Nov 1 09:23:06 EST 2013


Hello
I have recently read some Rasch digests about error at the cut point of the test. These suggest that to convert the Rasch logit S.E. at the cut point of the test to raw score units (or approximately)  one should take the reciprocal of the S.E. of the nominated logit value.
HOWEVER, as the S.E. gets smaller (good) the reciprocal gets bigger! And so the raw score range within the boderzone becomes larger. I must be missing something?
E.g we have a test with very small S.E. at cut logit measure of 0.05...  1/0.05 is 20- a borderzone of 40marks...whereas an S.E. of 0.15, hence 1/0.15  would give you a raw score range of 14...

Thanks!

IMOGENE ROTHNIE | Lecturer (Assessment)
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