Posted by
Poes, Matthew Joseph on
May 30, 2012; 1:44pm
URL: http://spssx-discussion.165.s1.nabble.com/COvaraince-not-Positive-definite-for-CFA-tp5713427p5713433.html
The problem is you have a data issue that is causing your 4 latent variables to over-tax the 14 variables that make them up. I don't know enough about these 14 variables, but you have some set of problems amongst one or all of them that is making it too difficult to extract the 4 latent variables. I would be sure there isn't a lack of variance, a constant, anything of that sort. I would also consider going back to the EFA and see if a simpler model worked as well, maybe a 2 or 3 LV model. Then test that.
I've heard different arguments on sample size for CFA. I've heard everything from 30 per LV with all variables meeting assumptions, 100 if they don't fully. I've heard 10 per manifest variable. I've heard 30 per manifest variable. There doesn't seem to be clear consensus on this, but your situation may indicate a power issue.
Matthew J Poes
Research Data Specialist
Center for Prevention Research and Development
University of Illinois
510 Devonshire Dr.
Champaign, IL 61820
Phone: 217-265-4576
email:
[hidden email]
-----Original Message-----
From: SPSSX(r) Discussion [mailto:
[hidden email]] On Behalf Of cicilia
Sent: Wednesday, May 30, 2012 4:27 AM
To:
[hidden email]
Subject: COvaraince not Positive definite for CFA
Hello All
Been through all the msgs for this NPD problem Tried the different soultions. I have N=200, 14 varaibles for a CFA. They go into 4 LV's.
Everything seems ok but I get NPD msg. Any suggestions?
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