[Rasch] Facets feature or bug?

Iasonas Lamprianou liasonas at cytanet.com.cy
Tue Apr 3 00:15:36 EST 2012

Dear all, 
in the first edition of Bond and Fox book (the one I have), the reference to Lunz et al. (1990) is not included. It is also not clear what the exact reference is for Linacre (1997). Could (anyone, if Trevor is not avaiable) confirm that we refer to those two references?

Linacre, M. (1997). MESA Release note #3. Reached at http://www.rasch.org/rn3.htm on April 2nd, 2012

Lunz, M.E., Wright, B.D., Linacre, J.M. (1990) Measuring the Impact of Judge Severity on Examination Scores. Applied Measurement in Education, 3(4), 331-345.

Also, at the risk of sounding naive (or even a little bit careless) I am not quite sure if I understand why this "minimal design" is enough to calibrate and compare the raters in the sense that each rater has seen a different set of observations. If anyone can offer me a simple explanation which I could also pass to other people if asked, that would be great.

Thank you, not only for your support, but also for your patience.


----- Original Message Follows -----
From: Iasonas Lamprianou <liasonas at cytanet.com.cy>
To: <rasch at acer.edu.au>
Subject: Re: [Rasch] Facets feature or bug?
Date: Mon, 2 Apr 2012 11:58:20 +0300
> thanx. googled it and found the tablea you mention. ----- Original Message Follows -----From: "Bond, Trevor" <trevor.bond at jcu.edu.au>To: "rasch at acer.edu.au" <rasch at acer.edu.au>Subject: Re: [Rasch] Facets feature or bug?Date: Mon, 2 Apr 2012 01:54:35 -0700> Sure, JasonAll your data seem to be linked via the studentsAs they are in the example givenCheck Mike's paperTOn 2/04/12 6:11 PM, "Iasonas Lamprianou" <liasonas at cytanet.com.cy> wrote:> > thank you Trevor> > i am afraid that i only have your edition one of the book, can i find this> information there as well? also i apologise for not understanding fully your> position so i need a clarification. your position is that it is not a bug and> facets can recover some useful info to compare the raters although no double> marking of any magnitude exists. am i missing something?> > -----
> Original Message Follows -----> From: "Bond, Trevor" <trevor.bond at jcu.edu.au>> To: "rasch at acer.edu.au" <rasch at acer.edu.au>> Subject: Re: [Rasch] Facets feature or bug?> Date: Mon, 2
>  Apr 2012 00:30:29 -0700>> 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 bo th 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. Linacre?s final table>> reveals the minimal judging plan
> , in which each of the 32 examinees? 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 tha t 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 judges? 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>>>
> 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 spa rse (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>>> _______________________________________________>>> Rasch mailing list>>> Rasch at acer. edu.au>>> Unsubscribe: >>> https://mailinglist.acer.edu.au/mailman/options/rasch/trevor.bond%40jcu.edu.>>> au>>> >> >> >> _______________________________________________>> Rasch mailing list>> Rasch at acer.edu.au>> Unsubscribe: >> https://mailinglist.acer.edu.au/mai lman/options/rasch/liasonas%40cytanet.com.>> cy>
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