Re: st: margins at every observation

[Thomas <tpt21@cam.ac.uk>]

> --- On Tue, 12/10/10, Thomas wrote:
> > I want to calculate the marginal effects for all
> > observations:
> >
> > sysuse auto, clear
> > reg price c.mpg##c.mpg
> >
> > gen dydx = _b[mpg]+2*_b[ c.mpg#c.mpg]*mpg
> >
> > I thought I would get the same using:
> >
> > margins, dydx(mpg) at((asobserved) mpg)
> >
> > but I only get a single value at the mean of mpg.
> >
> > How can I get the marginal effect at each observation from
> > -margins- (if at all)?
> That marginal effect only depends on the value of mpg, so
> you can get a complete list of all marginal effects by typing:
>
> margins, dydx(mpg) over(mpg)
>
> There is no -generate- or -replace- option in -margins, so there
> is no easy way to turn this into a variable (it is possible, but
> your manual computations are just easier).
>
> 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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Thanks. But it does not seem to allow negative values for the variable 
that is included in -over-. Is there any way around this?

Thomas
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