[Rasch] Rating scale and partial credit model with identical responses
rmt at rasch.org
Mon Jun 26 23:13:36 EST 2006
Thank you for your question - it addresses an important issue in
These "perfect" response strings are a problem for any type of analysis!
These response strings are like putting each student's MCQ bubble sheet
through an optical scanner 5 times, and then thinking that you had 5
observations of each student's responses to each item.
If you really have a dataset like this, then 4 of the 5 judges are
redundant, and their data should be eliminated. It provides no extra
You would then have only one statistically-independent observation of each
student. This is enough to order the students, but not enough to construct
a verifiably linear measurement system.
At 6/26/2006, you wrote:
>If on a set of polytomous items or Likert scale items students get the
>same score on each individual item, is it a problem for Rasch analysis?
>Suppose, the response vectors for 5 polytomous items for 5 respondents
>And this pattern continues for all respondents.
>This could well be the case when there is complete agreement among
>judges in rated performances, which could be the result of good training
>and the existence of a well defined rating scale.
>Tried the new MSN Messenger? It's cool! Download now.
>Rasch mailing list
>Rasch at acer.edu.au
Mike Linacre, mike at winsteps.com
Winsteps, PO Box 811322, Chicago IL 60681-1322
Tel. & FAX (312) 264-2352
Facets Introductory Workshop: www.winsteps.com/facwork.htm - July 28-29, 2006
Winsteps Introductory Workshop: www.winsteps.com/workshop.htm - Aug. 7-8, 2006
Winsteps Online Course: www.statistics.com/courses/rasch - July 21 - Aug.
Winsteps: www.winsteps.com/winsteps.htm - current version 3.61.1 - May 2006
Facets: www.winsteps.com/facets.htm - current version 3.61.0 - May 2006
Your comments and questions are welcomed.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Rasch