st: weights and ssm

[Erica Ryu <eryu@umich.edu>]

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.

Please advise. Thank you!

Erica
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