[Limdep Nlogit List] Ordered probit with sample selection

[William Greene]

Valentina. It looks like there are no observations with y=0
in the selected sample. 
/Bill Greene

----- Original Message -----
From: "Valentina Tartari" <v.tartari at imperial.ac.uk>
To: "limdep at limdep.itls.usyd.edu.au" <limdep at limdep.itls.usyd.edu.au>
Sent: Thursday, March 5, 2009 9:38:47 AM GMT -05:00 US/Canada Eastern
Subject: [Limdep Nlogit List] Ordered probit with sample selection

Dear all,

I am trying to estimate an ordered probit model with sample selection. The first step (probit) works fine, however when I try to run the second step I get this message: "Error 128: Models - Insufficient variation in dependent variable".

My dependent variable is coded 0,1,2,3 and if I run an ordered probit without the selection it works fine.

Any idea of what can be the problem?

Thank you a lot

Valentina






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