st: Re: RE: adjust after heckman

["Christer Thrane" <ch-thran@online.no>]

Thanks, Scott!

That worked nicely. I have a short follow-up, though.

Is it also possible, using your code, to set weight and length to specific 
values, and not only their means?

Thanks again,

Christer
----- Original Message ----- 
From: "Scott Merryman" <smerryman@kc.rr.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Friday, April 07, 2006 5:53 PM
Subject: st: RE: adjust after heckman



> Unfortunately, -adjust- does not have predict option, but you can
> -preserve-, -replace-, and -predict, ycond-.
>
> The following generates the conditional expectation for 5 values of mpg 
> with
> the other variables at their means.
>
> sysuse auto
> preserve
> qui heckman price mpg weight length , select(fore =  trunk )
> foreach v of varlist weight trunk length {
> sum `v', meanonly
> replace `v' = r(mean)
> }
> forv i = 10(10)50 {
> replace mpg = `i'
> predict ycond_`i', ycond
> }
> tabstat ycond*, stat(mean)
> restore
>
>
> Scott
>
>
>
>
> > -----Original Message-----
> > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
> > statalist@hsphsun2.harvard.edu] On Behalf Of Christer Thrane
> > Sent: Friday, April 07, 2006 9:22 AM
> > To: statalist@hsphsun2.harvard.edu
> > Subject: st: adjust after heckman
> >
> > Hi,
> >
> > Normally I use adjust (after -regress-) to predict the mean earnings for
> > variuos combinations of my indeps.
> > When doing this for -heckman- I suspect that adjust produces the
> > prediction
> > for the "latent" mean earnings
> > (ie regardless of if a person actually is employed or not). However, I
> > want
> > to get the mean earnings for the
> > variuos combinations of my indeps, condtitional on being employed (ie
> > being
> > observed).
> >
> > How do I do this?
> >
> > Best regards,
> >
> > Christer Thrane
>
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