Re: st: Fwd: Ologit mfx question

[Richard Williams <richardwilliams.ndu@gmail.com>]

You don't show your code, but I bet you did something like

use "http://www.indiana.edu/~jslsoc/stata/spex_data/ordwarm2.dta";, clear
ologit warm male
mfx

ologit is a multiple outcome command, and hence 
there are multiple marginal effects to compute. 
In this case the marginal effect tells that being 
male increases the likelihood of your being in 
category 1, which is consistent with what the 
coefficient estimates tell you. Instead, you ought to be doing something like

use "http://www.indiana.edu/~jslsoc/stata/spex_data/ordwarm2.dta";, clear
ologit warm male
mfx, predict(outcome(#1))
mfx, predict(outcome(#2))
mfx, predict(outcome(#3))
mfx, predict(outcome(#4))

Basically, the results tell you that being male 
increases the likelihood of being in the lower 2 
categories and decreases the likelihood of being 
in the upper 2, which is consistent with the 
negative coefficient for male in the ologit 
results, i.e. if you are less likely to be in one 
category you have to be more likely to be in another.

You can make life a little simpler by using 
either -margeff- or -mfx2-, both of which can be downloaded from SSC.

Since you are using mfx, I assume you are using 
Stata 10 or lower. But if you are using Stata 11 
or 12, the -margins- command is superior to 
-mfx-. But you still need to specify multiple outcomes.

At 09:41 PM 2/18/2013, ä¿?å?©,ä¿? Junli-Yu wrote:
> Dear Statalister,
>
>     The dependent var is Order value(0-1-2-3) ,and my key independent var is
> dummy var(0-1). I regress my dataset by ologit that shows the coeffience is
> positive significant relation, but by mfx shows the margin effect is
> negative significant relation.
>
> Whether it is wrong use mfx command. Because I recode my dependent var that
> change to dummy variable (0-1),both the coeffience and margin effect are
> same relation.
> *
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-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
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