Re: factor loadings

Richard Bell (
Tue, 04 Feb 1997 10:09:07 +1100

The problem usually occurs in the eigen-decomposition part of the program
where constants relating
to the hardware are stored. Programmers may set these differently. If the
loading signs are mirrored this is a trivial matter (since the signs are
arbitrary) and probably reflects a different number being used for the base,
but if they are not exactly mirrored then it is likely there is also a
differencein the constant used to decide when no further iterations are
needed. Hopefully your differences are not substantial.

Richard Bell

At 06:50 AM 1/27/97 +1000, you wrote:
>Advice is sought regarding what parameters can affect the signs in a
>PCA/factor analysis. I am trying to work out why the factor loading signs
>vary when two versions of the same program are applied to the same data.
>The loadings are not exactly mirrored.
>Bob Green
Richard C Bell
Department of Psychology
University of Melbourne
Parkville Vic 3052 Australia
Phone: +61 (0)3 9344 6364
Fax: +61 (0)3 9347 6618