Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

st: Re: Re: Why do Stata Cronbach's Alpha values not match SAS?


From   "Joseph Coveney" <jcoveney@bigplanet.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: Re: Re: Why do Stata Cronbach's Alpha values not match SAS?
Date   Fri, 29 Apr 2011 13:12:39 +0900

Benjamin Gramig wrote:

. . .

I feel I still need to use SAS for the accompanying PCA of the items in the
scale because I cannot figure out how to output factor loadings or apply
rotations following -polychoric pca-. It is my understanding that for
ordinal/Likert data I need to use polychoric correlations (or another technique)
to perform PCA correctly.

--------------------------------------------------------------------------------

According to the help file for Stas Kolenikov's -polychoricpca-, results are
available as returned matrixes.  

For rotation, if you've already downloaded -polychoricpca-, then you've
downloaded his -polychoric-, as well.  You can use the latter in tandem with
Stata's official -pcamat-, which works with -rotate- (and which also makes the
components available as a returned matrix).

Joseph Coveney

version 11.2

clear *
set more off
sysuse auto

polychoricpca rep78 foreign mpg
matrix list r(eigenvectors)

polychoric rep78 foreign mpg
pcamat r(R), n(`r(N)')
matrix list e(L)
estat loadings
rotate

exit


*
*   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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index