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| From | Justina Fischer <JFischer@diw.de> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | st: 'margin' and marg. effects of second-order polynomials |
| Date | Thu, 30 Dec 2010 00:30:23 +0100 |
Hi
I am estimating (using oprobit, unfortunately) a functional relationship of the following kind (simplified)
Pr(F) = ax + bx^2 + other stuff.
I am interested in the marginal effect: dPr(F)/dx = a + 2bx
Using margin, I get marginal effects as if x and x^2 were two separate variables, even though I interact the factor x (x##x) in my specification.
Is there a way to make 'margin' estimate dPr(F)/dx, taking into account the functional relationship ?
Browsing the Stata archive did not help....and calculating by hand is probably rather unfeasible.
Thanks
Justina