[Limdep Nlogit List] dummy coding vs effects coding
Kandice L. Kleiber
kleiberk at onid.orst.edu
Thu Jul 23 08:49:17 EST 2009
Hi -
So I have estimated a nested logit model and basically done everything
that I want to do ... except find the marginal effects of my
categorical variables.
One variable in question is education, and I have broken it down into
3 levels, eda, edb, edc, where eda is the lowest level of education.
In running my model I used eda as the base (ie dropped it from the
equations). I coded each new variable as a 0-1, thus if edb=1 then
eda=edc=0 and if eda=1 then edb=edc=0.
However, the code that I found to run the marginal effects uses
"effects code" ie making eda=-1 instead of =0. If you use the effects
coding and want to compare edb vs eda you use:
scenario: edb=1/edc=0 & edb=-1/edc=-1$
But since I have already run my model and have all my other results,
I'm wondering if I can still use this code, given that I have used
"dummy coding" (0-1 variables).
If so, can I use:
scenario: edb1/edc=0 & edb=0/edc=0$ ?
I guess I'm not sure if LimDep is doing the same thing that it would
with effects coding?
Any input would be appreciated!
Thanks!
Kandice.
---
Kandice L. Kleiber
Graduate Teaching Assistant
Department of Economics
Oregon State University
e: kleiberk at onid.orst.edu
w: 541.737.6628
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