On Mon, 21 Jul 2003 03:40:25 GMT, "Mousie"
> This may be a stupid question, but I can't seem to find the answer anywhere.
> When reporting the results of a factor analysis, specifically the percentage
> of varience the factor solution accounts for, do you report the extraction
> sums of squares % of varience or the rotated % of varience? Intuitively, I
> think it should be the rotated % of varience, but I would be most grateful
> for some input here.
The percent initially extracted is the one that says something
about the quality of the factoring. For a common-factor
interpretation, the total fraction should be about the same as
the reliability. You look at the cumulative percent to see that
it is 'reasonable,' and you look at the 'scree' at the to see
where the contribution drops stops.
> Also, with factor analysis when looking at the loadings on each factor, some
> of the items load on more than one item. What questions should I be asking
> if this happens?
"Are these items more ambiguous than they need to be?"
"Are these cross-loadings sensible?"
You do not say what it is that you are factoring. If they are
questions that you have composed, then you have a chance
to refine them.
If there are a lot of cross-loadings that I did not expect,
then I figure that the sample N is probably too small,
given the amount of structure ('correlations') that existed;
and this lack of delineation could be a consequence.
(Then I would drop a bunch of variables to see if the
other loadings become cleaner.)
"Taxes are the price we pay for civilization." Justice Holmes.