-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Michael Dewey
Sent: Sunday, November 28, 2004 10:28 AM
To: r-help-stat.math.ethz.ch
Subject: [R] Tetrachoric and polychoric ceofficients (for
sem) - any tips?
About two years ago there was a thread about this which
suggested that at that time nobody had these coefficients ready to go.
(a) has anyone in the meanwhile programmed them?
(b) I think I can see how to do the tetrachoric one with
mvtnorm on similar lines to an example on the help page so
will try that if nobody else already has
(c) looking at the polychoric one makes me realise yet again
that I wish I knew more mathematics. I would also find it
difficult to test it as I do not have any worked examples.
Does anyone have any tips about how to program it and how to
test the resultant code?
(d) I appreciate this last item is not strictly an R
question, but my intention is to use these as input into the
sem package for structural equation models. If anyone thinks
that is misguided I would be intersted to here.
Michael Dewey
m.dewey at iop.kcl.ac.uk