If you haven't done these yet:
1. Check that you have the latest versions of -ssm- and -gllamm-
2. Examine the distribution of your weight variable for the people in
the selection and outcome models.
I don't get an error running the example in the -ssm- help file with
a logit link and added pweight.
On 1/19/09, Erica Ryu <[email protected]> wrote:
Hello,
I am trying to do a logit model with sample selection and am using
the
following command (since I cannot use the svy prefix with ssm, I
use "if"
and pweight):
ssm yvar x1 x2 x3 if prot==1 [pweight=pawt2], s(frd=participation
rtrad_white ca_8 q7b) q(8) fam(bin) link (logit) sel
which then produces an "invalid" error message. I think there is
something
wrong with the way I included the pweight, because when I take out
[pweight=pawt2], the model runs fine.
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