Re: st: Different selection variables for different subpopulations in the sample

[Maarten buis <maartenbuis@yahoo.co.uk>]

--- On Sun, 17/4/11, Dimitrije Tišma wrote:
> I was wondering if there exists some Stata command which
> would allow me to select different selection variables when
> working with Heckman selection models. For instance, let's
> say I am working with the textbook example of wages. I may
> assume that number of kids is the variable that determines
> selection of women into employment, while some other
> variable would be selection variable for men. Or,
> alternatively, I could assume that there is selection bias
> only for women, while no selection is at work for the other
> part of the sample.

I would just add interaction terms between a female indicator 
variable and relevant other variables in your selection
equation, i.e. I would not expect the number of children to
have the same effect on the probability of working for men and
women.

Hope this helps,
Maarten

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

http://www.maartenbuis.nl
--------------------------

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