--- "Ana R. Rios" <[email protected]> wrote:
> I am trying to use oheckman but I am getting the
> following message:
> "Warning: Estimate of rho1 = . is outside feasible
> interval [-1, 1]."
> I would appreciate any suggestions/insights on how to
> overcome this problem.
It seems that -oheckman- has "converged" to an
infeasible solution. The solution is to estimate a
better model, as you haven't told us anything about
your model I can't be very specific. One thing that
jumps to mind with any heckman-like model is to make
sure your model is properly identified, i.e. use
instruments instead of relying on non-linearity.
Another thing you might want to look at is to use
the -twostep- option and see if that leads to any
better estimates.
-- Maarten
BTW. -oheckman- is not in official Stata, so tell
us where you got it.
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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