[R] Link functions in SEM

[John Fox]

Dear Jeroen,

It's true that the sem() function only handles quantitative endogenous
variables, but you could use it along with functions in the polycor package
to fit models with ordered or dichotomous observed variables. There's an
example of a confirmatory factor analysis model with ordinal indicators in
the paper at <http://socserv.mcmaster.ca/jfox/Misc/sem/SEM-paper.pdf>.

I hope this helps,
 John

------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
web: socserv.mcmaster.ca/jfox


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
> Behalf Of Jeroen Ooms
> Sent: July-27-08 2:52 PM
> To: r-help at r-project.org
> Subject: [R] Link functions in SEM
> 
> 
> Is it possible to fit a structural equation model with link functions in
R? I
> am trying to build a logistic-regression-like model in sem, because
> incorporating the dichotomous variables linearly seems inappropriate.
Mplus
> can do something similar by specifying a 'link' parameter, but I would
like
> to be able to do it in R, ofcourse.
> 
> I have explored the 'sem' package from John Fox, but it does not seem to
be
> able to fit non-linear relations. Is there some R-package or way to get
this
> done? I have also considered creating a seperate latent variable in the
sem
> model for the systematic component of the predictors, but then I still
need
> a way to fix a non-linear link from the systematic component to the
> dichotomous Y variable.
> --
> View this message in context: http://www.nabble.com/Link-functions-in-SEM-
> tp18679236p18679236.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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