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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The residuals contain information not accounted for by the Rasch scale. If there is coherent information in those residuals, it could lead to exploring additional scales. The variance in the person scale is that which is attributable to the underlying construct. Given that the factors were correlated there at least two potential models of explanation. First there could be a second order factor to account for those correlations. Or you could have a general factor with a number of specific factors. If it is the common variance among the items that you are interested in then the Rasch scale should capture that even in the presence of specific factors.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p>&nbsp;</o:p></span></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dr. Paul R. Swank, <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Children's Learning Institute<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Professor, Department of Pediatrics, Medical School<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Adjunct Professor, School of Public Health<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>University of Texas Health Science Center-Houston<o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p>&nbsp;</o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Juanito Talili [mailto:talilij@yahoo.com] <br><b>Sent:</b> Thursday, November 17, 2011 10:46 PM<br><b>To:</b> Swank, Paul R; Rasch Forum<br><b>Subject:</b> Re: [Rasch] Rasch analysis then EFA<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p>&nbsp;</o:p></p><div><div><p class=MsoNormal style='background:white'><span style='color:black'>My apology for the low level questions:<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>1. What is the logic why the residuals of the Rasch analysis are subjected for EFA?&nbsp; Why not the&nbsp;person or item measures?&nbsp;<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>2. The factors in the previous analysis were correlated.&nbsp;Should I do Rasch on the combined items?<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>Thank you.<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'>J<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='color:black'><o:p>&nbsp;</o:p></span></p></div><div><div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'> &quot;Swank, Paul R&quot; &lt;Paul.R.Swank@uth.tmc.edu&gt;<br><b>To:</b> Juanito Talili &lt;talilij@yahoo.com&gt;; Rasch Forum &lt;rasch@acer.edu.au&gt; <br><b>Sent:</b> Thursday, November 17, 2011 10:41 PM<br><b>Subject:</b> RE: [Rasch] Rasch analysis then EFA</span><span style='color:black'><o:p></o:p></span></p><div id=yiv1244042659><div><div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>I would do the Rasch on all classes in order to increase heterogeneity of responses. And I would suggest EFA on the residuals of the Rasch analysis. It all depends on whether the factors are correlated so that it is possible there is an underlying latent variable with perhaps some specific factors. If the factors in the previous analysis were uncorrelated, then I would think twice before using Rasch on the combined items.</span><span style='color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>&nbsp;</span><span style='color:black'><o:p></o:p></span></p></div><div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Dr. Paul R. Swank, </span><span style='color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Children's Learning Institute</span><span style='color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Professor, Department of Pediatrics, Medical School</span><span style='color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Adjunct Professor, School of Public Health</span><span style='color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>University of Texas Health Science Center-Houston</span><span style='color:black'><o:p></o:p></span></p></div></div><div><p class=MsoNormal style='background:white'><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>&nbsp;</span><span style='color:black'><o:p></o:p></span></p></div><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><div><p class=MsoNormal style='background:white'><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'> rasch-bounces@acer.edu.au [mailto:rasch-bounces@acer.edu.au] <b>On Behalf Of </b>Juanito Talili<br><b>Sent:</b> Wednesday, November 16, 2011 11:57 PM<br><b>To:</b> Rasch Forum<br><b>Subject:</b> [Rasch] Rasch analysis then EFA</span><span style='color:black'><o:p></o:p></span></p></div></div></div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div><div><div><div style='margin-bottom:12.0pt'><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>Opps!! I forgot to indicate the subject.</span><span style='color:black'><o:p></o:p></span></p></div><div id=yiv1244042659><div><div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>Dear All,<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>A self-administered &quot;Computer Laboratory Usability Questionnaire&quot; consists of 43 five-point ordinal scale items (1=strongly disagree to 4 strongly agree).&nbsp; The instrument, moreover, consists of six factors with the following number of items: 3, 3, 4, 7, 12, and 15.&nbsp; The questionnaire was developed using CTT.<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>My Concerns:<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>1) Now, I want to re-validate the instrument using Rasch Model.&nbsp; My sample now is already more than 3000.&nbsp; The samples are students who rated six different computer laboratories (LAB1, LAB2....LAB6).&nbsp; Shall I use only sample from one LAB?<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>2. Can I do the Rasch analysis for the 43 items as if unidimensional?&nbsp; Then, do an EFA using the resulting measures?&nbsp; The EFA will be used to check if the items are really loaded to the expected factor.<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>Your comments are highly solicited.<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>Thank you.<o:p></o:p></span></p></div></div><div><div><p class=MsoNormal style='background:white'><span style='color:black'>J<o:p></o:p></span></p></div></div></div></div></div><div style='margin-bottom:12.0pt'><p class=MsoNormal style='background:white'><span style='color:black'>&nbsp;<o:p></o:p></span></p></div></div></div></div></div></div></div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><span style='color:black'><o:p>&nbsp;</o:p></span></p></div></div></div></div></body></html>