Also, factanal() does not do `principal component analysis', and it may well be that the data are inappropriate for factor analysis if they are appropriate for PCA.

If PCA was really intended, prcomp() and princomp() are appropriate tools.

On Tue, 30 Nov 2004, Andy Bunn wrote:

It looks like factanal is unable to optimize from these starting values
(kinda like the error message says). So, factanal.fit.mle isn't converging
and you have problems with your analysis. Try putting control = list(trace =
T) in your code to see what happenens. E.g.,

R >
R >      v1 <- c(1,1,1,1,1,1,1,1,1,1,3,3,3,3,3,4,5,6)
R >      v2 <- c(1,2,1,1,1,1,2,1,2,1,3,4,3,3,3,4,6,5)
R >      v3 <- c(3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,5,4,6)
R >      v4 <- c(3,3,4,3,3,1,1,2,1,1,1,1,2,1,1,5,6,4)
R >      v5 <- c(1,1,1,1,1,3,3,3,3,3,1,1,1,1,1,6,4,5)
R >      v6 <- c(1,1,1,2,1,3,3,3,4,3,1,1,1,2,1,6,5,4)
R >      m1 <- cbind(v1,v2,v3,v4,v5,v6)
R >      factanal(m1, factors=3, control = list(trace = T))
start 1 value: 0.4755156 uniqs: 0.0050 0.1009 0.0050 0.2241 0.0843 0.0050

Call:
factanal(x = m1, factors = 3, control = list(trace = T))

Uniquenesses:
  v1    v2    v3    v4    v5    v6
0.005 0.101 0.005 0.224 0.084 0.005

Loadings:
  Factor1 Factor2 Factor3
v1 0.944   0.182   0.267
v2 0.905   0.235   0.159
v3 0.236   0.210   0.946
v4 0.180   0.242   0.828
v5 0.242   0.881   0.286
v6 0.193   0.959   0.196

              Factor1 Factor2 Factor3
SS loadings      1.893   1.886   1.797
Proportion Var   0.316   0.314   0.300
Cumulative Var   0.316   0.630   0.929

The degrees of freedom for the model is 0 and the fit was 0.4755
R >

If you think the model should be OK and there isn't an error somewhere else
then you'll want to fiddle with the control options. From the help for
fractanal:

control: A list of control values,

         nstart The number of starting values to be tried if 'start =
              NULL'. Default 1.

         trace logical. Output tracing information? Default 'FALSE'.

         lower The lower bound for uniquenesses during optimization.
              Should be > 0. Default 0.005.

         opt A list of control values to be passed to 'optim''s
              'control' argument.

         rotate a list of additional arguments for the rotation
              function.

    ...: Components of 'control' can also be supplied as named
         arguments to 'factanal'.


HTH, Andy


-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Catherine Dempsey
Sent: Tuesday, November 30, 2004 7:31 AM
To: '[EMAIL PROTECTED]'
Subject: [R] Info


I am having difficulty obtaining the scores from my principal component analysis. I have used this method before and have had no problems. The data set that I am using this time is similar to what I have used in the past. What do I need to do to my dataset in order for me to obtain these scores?

R screen says the following message

Error in factanal(covmat = pasa.cov, factors = 4) :
        Unable to optimize from these starting value(s)

many thanks

Catherine


KSS Ltd Seventh Floor St James's Buildings 79 Oxford Street Manchester M1 6SS England Company Registration Number 2800886 Tel: +44 (0) 161 228 0040 Fax: +44 (0) 161 236 6305 mailto:[EMAIL PROTECTED] http://www.kssg.com


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