[Rasch] Relative Examiner severity after group anchoring in FACETS

Imogene Rothnie imogene.rothnie at sydney.edu.au
Thu May 12 17:55:55 AEST 2016

Hello all, here is one for the FACETS users.

Just wanting to confirm the following, or tell me if I have misunderstoodŠ

I have an OSCE with examiners nested in sites and stations , and students
nested in sites, although students and stations are crossed.
I always get a subset disconnection that mostly equates to sites, apart
from a few odd examiners who make their own subset (!)
When I group anchor on Examiners , I always get Œsubset connection OK¹.

HOWEVER , this just means each group now has an anchored mean of zero yes?
And an examiner severity measure of 1.0 in group A, would only be 0.5
logits more severe than examiners with 0.5 logit severity IN THAT GROUP.
Examiner severity across subset groups even after subset anchoring does
not mean a severity logit of 1.0 in Group A = examiner severity logit of
1.0 for an exminer group B. Yes?

But what of student measures? If they are crossed across stations and does
that provide enough rectangulation to consider their measures across the
entire cohort even though they are also nested in site?

Many thanks for your opinions..

IMOGENE ROTHNIE B.A./B.Sci. Grad. Dip. (Psych.)  M.ED. (Assess & Program
Senior Lecturer, Assessment
Education Office (Tuesday ­ Friday)
Sydney Medical School
Rm 108, Edward Ford Building (A27) | The University of Sydney | NSW | 2006

T +61 2 9036 6434  | M +61 418 381 359
(mobile best contact)


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