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Re: st: biprobit with partial observability

From   Maarten buis <>
Subject   Re: st: biprobit with partial observability
Date   Sun, 22 Nov 2009 11:46:00 -0800 (PST)

--- On Sun, 22/11/09, Celia Vera wrote:
> I am estimating a bivariate probit for a two-stage process
> in which the second event is observed conditional on the
> outcome of the first one (the first event is leaving the
> workforce (left) and the second event is returning to the
> workforce (ret). So, return only happens if the person left
> the workforce).
> I understand i have to use a biprobit model with partial
> observability. 
> but the likelihood function never converges (it is not
> concave) in all the iterations.

The help file warns that this model often won't converge
and advises to use the -dificult- option. Alternatively
you could look at -heckprob-.

Hope this helps,

Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen


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