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# Re: st: MIXLPRED: marginal effects after-MIXLOGIT-

 From Arne Risa Hole To statalist@hsphsun2.harvard.edu Subject Re: st: MIXLPRED: marginal effects after-MIXLOGIT- Date Wed, 29 Feb 2012 11:01:57 +0000

```Dear Kayo,

Most importantly: what is the unit of measurement of the income
variable? If income is measured in dollars or euros (or yen), for
example, you would expect the marginal effect of a one unit increase
in income to be small. See Richard Williams' reply to my earlier post
on calculating marginal effects after -mixlogit-.

Arne

2012/2/29 nagi kayo <kayonagi@hotmail.co.jp>:
> Dear Professor Arne Risa Hole and all
>
>
>
> I read the thread Professor Hole kindly wrote on "Mon, 6 Feb. 2012 13:18:34" about calculating marginal effects after -mixlogit- and tried to calculate marginal effects using the following commands.  in my estimation model, the number of alternatives is four, and "inc" is a demographic variable, and "price" is an alternative specific variable.
>
>
>
> mixlogit d d1inc d2inc d3inc, group(id) rand(price)
> mixlpred pred_base
>
> replace d1inc=d1inc+1
> replace d2inc=d2inc+1
> replace d3inc=d3inc+1
> replace d4inc=d4inc+1
> mixlpred pred_inc
>
>
> however, unexpectedly, "pred_inc" is quite similar to "pred_base," and thus the difference between the two is almost zero, which means that the marginal effect of income is almost zero.
>
> although i also tried the other explanatory variables, the results are not changed (in all cases, marginal effects are almost zero).
>
> is my calculation of predicted probabilities wrong?
>
>
>
> i greatly appreciate it if you would give me your advice.
>
>
>
> with best wishes,
>
> Kayo
>
>
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