Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of gregor rolshausen
> Sent: Tuesday, January 13, 2009 8:41 AM
> To: r help
> Subject: [R] PCA loadings differ vastly!
>
> hi, I have two questions:
>
> #first (SPSS vs. R):
>
> I just compared the output of different PCA routines in R (pca, prcomp,
> princomp) with results from SPSS. the loadings of the variables differ
> vastly! in SPSS the variables load constantly higher than in R.
> I made sure that both progr. use the correlation matrix as basis. I
> found the same problem with rotated values (varimax rotation and rtex=T
> rotation).
>
> can anyone comment ?
>
> second:
>
> princomp(data, cor=T, rtex=T)$loadings vs. princomp(data, cor=T,
> rtex=F)$loadings
>
> gives me different loadings (expected because of rotation) with one
> dataset (11 variables)
> but returns the SAME values with another dataset (3 variables).
>
> comments ??
>
> thanks for your time!
>
> cheers,
> gregor
>
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