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# Re: st: predict after mlogit estimation

 From Richard Williams <[email protected]> To [email protected], [email protected] Subject Re: st: predict after mlogit estimation Date Fri, 16 Mar 2012 06:49:10 -0500

```At 04:09 AM 3/16/2012, Chiara Mussida wrote:
```
```Thank you Richard,
this seems to be the solution. Anyway, is it possible to check whether
the results obtained for p1 p2 p3 are the ones I need (male
coefficients*female individual characteristics)?
Male coefs are in the stata output, whilst female characteristics in
my dataset. Should I compute the product between the coefs in the
output and the average individual characteristics of female?

Thanks to you all
chiara
```
```
If you want a 2nd opinion, try

use "http://www.indiana.edu/~jslsoc/stata/spex_data/ordwarm2.dta";, clear
mlogit warm yr89 white age ed prst if male == 1
predict p1 p2 p3 p4 if male==0
sum p1 p2 p3 p4
margins if male == 0, noesample predict(outcome(1))
margins if male == 0, noesample predict(outcome(2))
margins if male == 0, noesample predict(outcome(3))
margins if male == 0, noesample predict(outcome(4))

```
Note that this is NOT the same as plugging in the average individual characteristics of females. If you wanted to do that, the commands would be
```
margins if male == 0, noesample predict(outcome(1)) atmeans
margins if male == 0, noesample predict(outcome(2)) atmeans
margins if male == 0, noesample predict(outcome(3)) atmeans
margins if male == 0, noesample predict(outcome(4)) atmeans
* verify that female means were used by margins
sum yr89 white age ed prst if male==0

```
With the first approach, you are computing a prediction for each case and then averaging the predictions. With the 2nd approach, you are computing the predicted value for a person who had average values on all the independent variables. I generally prefer the first approach. It often doesn't make that much difference in practice, but sometimes it will.
```
```
If you want yet a 3rd opinion, I suppose you could do the calculations for a few cases, or write your own gen command instead of using predict.
```

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Richard Williams, Notre Dame Dept of Sociology
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```