[Rasch] Facets feature or bug?

Iasonas Lamprianou liasonas at cytanet.com.cy
Mon Apr 2 18:02:57 EST 2012





thank you for the advice but the whole idea is that i want to compare the markers. i cannot anchor them at zero


-- Original Message Follows -----
From: Purya Baghaei <puryabaghaei at gmail.com>
To: <rasch at acer.edu.au>
Subject: Re: [Rasch] Facets feature or bug?
Date: Mon, 2 Apr 2012 12:20:14 +0430
> Hi Jason,
> I think you should use group-anchoring. Set that the mean leniency of
> the raters is the same. Anchor the raters at 0. This should take care
> of the unconnected data.
> 
> Purya
> 
> On 4/2/12, Bond, Trevor <trevor.bond at jcu.edu.au> wrote:
> > Jason, I think this covers it:
> > Linacre (1997) displayed three judging rosters for ratings from the Advanced
> > Placement Program of the College Board. The complete judging plan of 1,152
> > ratings illustrates the ideal plan for both conventional and Rasch analysis.
> > This complete judging plan meets the connection requirement between all
> > facets because every element (essays, examinees, and judges) can be compared
> > directly and unambiguously with every other element.
> > A much less judge-intensive plan of only 180 ratings also is displayed, in
> > which less precise Rasch estimates can be obtained because the facet-linking
> > overlap is maintained. The Rasch measures would be less precise than with
> > complete data because 83% fewer observations are made. LinacreΉs final table
> > reveals the minimal judging plan, in which each of the 32 examineesΉ three
> > essays is rated by only one judge. Each of the 12 judges rates eight essays,
> > including two or three of each essay type, so that the examinee­judge essay
> > overlap of these 96 ratings still enables all parameters to be estimated
> > unambiguously in one frame of reference.
> > Of course, the saving in judgesΉ costs needs to be balanced against the cost
> > of low measurement precision, but this plan requires only 96 ratings, 8% of
> > the observations required for the complete judging plan. Lunz et al. (1998)
> > reported the successful implementation of such a minimal judging plan
> > (Linacre, 1997).
> > B&F 2 p149
> >
> >
> > On 2/04/12 4:53 PM, "Iasonas Lamprianou" <liasonas at cytanet.com.cy> wrote:
> >
> >>
> >> Dear all,
> >> I send this question to all, and not only to Mike, because this question
> >> is
> >> both related to the Facets software, but is a methodological question as
> >> well.
> >>
> >> I am running a "typical" scenario where I have markers who mark the
> >> responses
> >> of students to a test. The markers do not see the whole test, but only
> >> individual questions. We do NOT have double marking. So, lets say that we
> >> have
> >> 1000 students, each one responding to 10 questions. In effect, we have
> >> 10.000
> >> responses. Lets say that each one of the 10.000 responses is randomly sent
> >> once to one marker. We have 20 markers in total.
> >>
> >> Observation 1: the 3-d matrix markersXitemsXstudents is VERY sparse (we
> >> will
> >> all agree on that) because we have NO double marking
> >> Observation 2 which is a question as well: I think that the design is NOT
> >> linked (no double marking), does everyone agree? However, Facets does not
> >> complain about disconnected subsets, I do not know why. Should I not
> >> worry?
> >> Does Facets assume that because of randomness, all markers are on the same
> >> scale? Is Facets confused and incorrectly thinks that the design is NOT
> >> disconnected?
> >>
> >> Question: If disconnected subsets is a problem in this case, how can I run
> >> an
> >> anlysis in order to identify marker effects using this dataset?
> >>
> >> Thank you for your help
> >>
> >> Jason
> >> _______________________________________________
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> >> Rasch at acer.edu.au
> >> Unsubscribe:
> >> https://mailinglist.acer.edu.au/mailman/options/rasch/trevor.bond%40jcu.edu.au
> >>
> >
> >
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> 
> 
> -- 
> Purya Baghaei, Ph.D
> English Department,
> Islamic Azad University,
> Ostad Yusofi St.
> 91871-Mashhad, Iran.
> Phone: +98 511 6635064-5
> Fax: +98 511 6634763
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