[R] starting values for uniquenesses in factanal()

[Barry Cooke]

Dear R-help,

Using R 1.2.1 on Windows98 to run a factor analysis on a 64x150 matrix of
data generated from a simulation model, factanal() reported that it failed
to find a solution.  Looking at the factanal code, I see the immediate
condition that triggered the result:

if (best == Inf)
        stop("Unable to optimize from these starting value(s)")

So I am sure factanal() is giving the intended result.  What I want to know
is what sort of data properties lead to this result, and how does one go
about choosing starting uniqueness values so that a (good) result can be
computed?  The factanal() help, in describing parameter "start", says it is:

NULL or a matrix of starting values, each column giving an initial set of
uniquenesses.

But (due to my own ignorance) this is a little sketchy.  Any references or
advice is appreciated.

I realize this is not strictly an R-question ... so far.  But because I did
not encounter the same problem using Minitab's factor analysis, I am curious
as to the reason for the different behaviour (and this is an R question).
Maybe the response I got from R's factanal() is actually more appropriate?
Is this another case of commercial software giving me an answer I want, even
if it's not a good one?  (I would prefer to use only R for the paper I am
writing.)  Any comments appreciated.  To spare bandwidth I don't post the
data here, but I can send it privately.

Barry J. Cooke
University of Alberta
Edmonton, AB, Canada
http://www.ualberta.ca/~bcooke

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