The reason I was working with a correlation matrix is because I wanted
to calculate polychoric correlations first before submitting it to the
actual sem command. I was unsure whether R would use polychoric
correlations when indicating which of the variables are ordered. A final
question on the sample.cov=hetcor command. Does this not assume it is a
sample variance-covariance rather than a correlation matrix (as
calculated using the polycor package)?

Yes. Sample.cov should always be a covariance matrix, not a correlation matrix. It is pretty useless for categorical data.

I also tried using the command (thanks for the tip!)

sem.cdu= sem(cdu, data=germany2009, ordered=c("cdupid", "MERKELLIKE",
"CDULIKE", "MERKELPROX", "CDUPROX"))

but I always get the error result:

semcdu=sem(cdu, data=germany2009, ordered=c("cdupid", "MERKELLIKE",
"CDULIKE", "MERKELPROX", "CDUPROX"), fixed.x=F)
Error in tmp[cbind(REP$row[idx], REP$col[idx])] <- partable$free[idx] :
   NAs are not allowed in subscripted assignments

It looks like you have some issues with your model specification. Could you remove all '~~' statements and try again?

If the problem remains, please send me your R script, and a snippet of the data (just enough to replicate the error).

Yves.

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Reply via email to