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From |
"Martin Weiss" <martin.weiss1@gmx.de> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: RE: Negative eigen values in factor, pf command? |

Date |
Wed, 29 Apr 2009 00:21:14 +0200 |

<> "PS. if "Thanks emails" are inappropriate for the listserv, please let me know off list and I'll refrain in the future...as I feel I will be asking more questions soon)"

toward the end:

I hope that you will continue asking questions on the list :-) HTH Martin _______________________

To: <statalist@hsphsun2.harvard.edu> Sent: Wednesday, April 29, 2009 12:15 AM Subject: Re: st: RE: Negative eigen values in factor, pf command?

Thanks to all for the multiple and prompt answers. The latter posts arelosing me, but they may be of interest to more statistically curiousresearchers (by the way, I did also try a factor, ml command, and theresults also seemed different than the pca results). The basicexplanation of what was going on with the factor command was helpful tounderstand the negative eigen values and unblocked the discussion with mystatistician colleagues. I basically wanted to check the dimensionalityof an index for a latent concept. I am going to put more stock in the pcaresults, and after looking at the factor loadings, I feel in a betterposition to interpret the results.Thanks (PS. if "Thanks emails" are inappropriate for the listserv, pleaselet me know off list and I'll refrain in the future...as I feel I will beasking more questions soon)Cheers, Jean-Gael "JG" Collomb PhD candidateSchool of Natural Resources and Environment / School of Forest Resourcesand ConservationUniversity of Florida jgcollomb@gmail.com jg@ufl.edu +1 (352) 870 6696 On Apr 28, 2009, at 3:43 PM, Verkuilen, Jay wrote:Michael I. Lichter wrote:So what are you advocating instead? ML, which isn't very robust toweirdness (technical term) in the data? Or something other than >FA/ PCA? No, I'm following the research of people like Rod McDonald (retired to his beloved Sydney), Albert Maydeu-Olivares (Barcelona) and Bud McCallum (UNC-Chapel Hill), who support the use of the Unweighted Least Squares criterion function, or multi-stage estimation methods that uses ULS followed by a few iterations of ML or GLS. ULS is mathematically equivalent to MINRES. Stata doesn't have ULS/MINRES (alas). One of the downsides to ULS is the fact that it doesn't generate standard errors and GoF statistics, but Albert's been rectifying that situation in a sequence of articles in various journals (Psychometrika, JASA, etc.): http://www.ub.edu/gdne/psicometriaen.html. * * 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/* * 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/

* * 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/

**Follow-Ups**:**Protocol [was: RE: st: RE: Negative eigen values in factor, pf command?]***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**References**:**st: Negative eigen values in factor, pf command?***From:*Jean-Gael Collomb <jg@ufl.edu>

**st: RE: Negative eigen values in factor, pf command?***From:*"Verkuilen, Jay" <JVerkuilen@gc.cuny.edu>

**Re: st: RE: Negative eigen values in factor, pf command?***From:*"Michael I. Lichter" <mlichter@buffalo.edu>

**RE: st: RE: Negative eigen values in factor, pf command?***From:*"Verkuilen, Jay" <JVerkuilen@gc.cuny.edu>

**Re: st: RE: Negative eigen values in factor, pf command?***From:*Jean-Gael Collomb <JG@ufl.edu>

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