Jonny Beber

Questions and Answers (5) View all

• Answer added in Reliability
  45 What should I do to perform a confirmatory factor analysis using SPSS?
  By Merche Ovejero · Complutense University of Madrid
  Jonny Beber · eHarmony Labs

  Like the previous posters have said, a CFA is not available in SPSS, you would have to get AMOS, LISREL, or MPlus. In regards to obtaining 58 facto... [more]

  Like the previous posters have said, a CFA is not available in SPSS, you would have to get AMOS, LISREL, or MPlus. In regards to obtaining 58 factors rather than your 24 that you're expecting, what type of exploratory factor analysis are you using? What factor extraction method and what method of estimating communalities? I would recommend Floyd & Widaman (1995) as a great summary of all the different methods and intricacies of Factor Analysis. Instead of looking at communalities that are above 1.0 or .7 (which isn't the most reliable way of doing so), examine the scree plot, and consider running a parallel analysis. The syntax for a parallel analysis can be found on Brian O'Connor's website: https://people.ok.ubc.ca/brioconn/nfactors/nfactors.html Floyd & Widaman (1995) can be found here: http://psychology.ucdavis.edu/labs/widaman/mypdfs/wid079.pdf
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• Answer added in Psychometrics
  5 Converting past test takers to ability scores using IRT
  By Jonny Beber · eHarmony Labs
  Jonny Beber · eHarmony Labs

  Ha ha, yeah, I realized there's a lot behind what I was looking for. There are so many ways of estimating theta, and from what I've read so far, Weig... [more]

  Ha ha, yeah, I realized there's a lot behind what I was looking for. There are so many ways of estimating theta, and from what I've read so far, Weighted Likelihood Estimation or (a form of) Maximum Likelihood may be the route to go (Bayesian methods, like EAP and MAP, seem to be more biased at extremes of theta). But I was seeing if anyone out here knew of a good explanation of it and maybe an example of how theta is calculated using either of these methods. But I'll definitely check out that book, thanks so much for the recommendation!
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• Answer added in Psychometrics
  5 Converting past test takers to ability scores using IRT
  By Jonny Beber · eHarmony Labs
  Jonny Beber · eHarmony Labs

  My model doesn't include Rasch properties, so to get the initial item parameters, I used the Graded Response Model. Given that I have the original re... [more]

  My model doesn't include Rasch properties, so to get the initial item parameters, I used the Graded Response Model. Given that I have the original responses to the items, and the item parameters based on the GRM, what are the best ways to estimate theta from these? Would it be more straightforward to do IRT for summed scores as explained in Thissen, Pommerich, Billeaud, & Williams (1995)?
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• Question asked in Psychometrics
  5 Converting past test takers to ability scores using IRT
  If I have the item parameters for a set of polytomous questions, how can I mathematically convert a set of previous responses to ability scores? I ha... [more]
  If I have the item parameters for a set of polytomous questions, how can I mathematically convert a set of previous responses to ability scores? I have looked into different types of estimation methods, and from what I read EAP, MAP, and ML all perform similarly with higher amounts of items. I'm looking to create my own program to convert these old responses to ability scores based on the IRT analysis of these items I have done. So I have the item parameters for these specific items, as well as their responses, does anyone have a straightforward explanation of how these can be used in estimating theta?
  By Jonny Beber · eHarmony Labs
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• Answer added in Psychometrics
  22 Item Response Theory
  By Lokesh Gupta · Maharshi Dayanand University
  Jonny Beber · eHarmony Labs

  It depends on what kind of polytomous data you are looking at, from what I know of BILOG, it doesn't do polytomous data. I would recommend IRTpro, or ... [more]

  It depends on what kind of polytomous data you are looking at, from what I know of BILOG, it doesn't do polytomous data. I would recommend IRTpro, or MULTILOG. If you are trying to look for free software, there is a R package, ltm, that handles all types of IRT analyses in R.
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