José C. <[email protected]> asks:
> I am estimating a regression that has no-lineal (or product of
> variables) variables in their dependent terms - for example:
>
> regress y x xz
>
> The program Stata doesn't allow logical operators in the command
> regress (or other equation terms as probit) and for that it is
> previously necessary to define the variable (for example: gen w = xz).
> However, if the interest is to calculate marginal effects or
> elasticities (using mfx or margeff or dprobit) - that procedure
> invalidates the results because the terms no lineal they are not
> considered (for example: dy/dx = 1 + z and no 1).
Using margeff may help. Let m be the mean or median or another typical value of z.
Then after any regression, you could calculate dy/dx as follows:
margeff, replace
lincom x+m*z
Tamas
------------------------------------------------
Tamas Bartus, PhD
Associate Professor, Institute of Sociology and Social Policy
Corvinus University, Budapest
1093 Budapest, Közraktár utca 4-6.
Phone: +36-1-482-7301
Fax: +36-1-482-7348
Homepage: www.uni-corvinus.hu/bartus
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