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| From | "Seed, Paul" <paul.seed@kcl.ac.uk> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | Re: st: Identifying the best scale without a "gold standard" |
| Date | Thu, 17 Nov 2011 14:21:11 +0000 |
Thank you Ronan (and Nick) for pointing me to some useful software. And Jean-Benoit for writing it. I agree about -clv- . It identified a single factor as the best representation, but also suggested a possible second factor, based on two scales with a higher than average correlation. All with the simplest possible format. BW Paul Seed Ronan Conroy <rconroy@rcsi.ie> wrote: Date Thu, 17 Nov 2011 10:48:26 +0000 >>On 2011 Samh 16, at 18:15, Cameron McIntosh wrote: >> Hayton, J.C., Allen, D.G., & Scarpello, V. (2004). Factor Retention Decisions in Exploratory Factor Analysis: a Tutorial on Parallel Analysis. Organizational >>Research Methods, 7(2), 191-205.http://orm.sagepub.com/content/7/2/191.full.pdf+html >A very well worthwhile article. The authors make the point that "Specifying too few factors results in the loss of important information by ignoring a factor or >combining it with another (Zwick & Velicer, 1986). This can result in measured variables that actually load on factors not included in the model, falsely loading >on the factors that are included, and distorted loadings for measured variables that do load on included factors. Furthermore, these errors can obscure the true >factor structure and result in complex solutions that are difficult to interpret (Fabrigar et al., 1999; Wood, Tataryn, & Gorsuch, 1996)." > >I really like Jean-Benoit Hardouin's -clv- command in this context, giving a splendid visual display of the structure of the items. It has revealed important >features of data, such as factors-within-factors, that would have been far harder to spot in the output of any factor analytic command. Ronán Conroy rconroy@rcsi.ie Associate Professor Division of Population Health Sciences Royal College of Surgeons in Ireland Beaux Lane House Dublin 2 * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/