>>> "email@example.com" <paige.miller@ITT.COM> 10/25/2005 10:25:13 AM
I cannot imagine how, on realistic data sets, SAS, MATLAB and R would
differ in ACCURACY for PCA or factor analysis with rotations. These
packages all have been written by professionals who know the proper
to write such code, and have been used extensively without a red
warning flag being raised that there are problems in one package or
another. I think you are wasting your time looking for differences.
PRECISION, on the other hand, may be different between the packages,
but do you really care if the packages differ in the 9th decimal
I am not so sure about this; Paige may be absolutley right, but.....
Do all these packages use the same algorithms for doing all the
background work behind a factor analysis and rotation?
Do they all have the same degree of numerical precision?
There could be differences without raising any red flags, because few
people do their FA on two packages, and the results from many packages
might be reasonable, but different one from the other.
Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core
Center for Drug Use and HIV Research
National Development and Research Institutes
71 W. 23rd St
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)