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# Re: st: what does Stata do with the fixed-effect in Xtlogit

 From Klaus Pforr <[email protected]> To [email protected] Subject Re: st: what does Stata do with the fixed-effect in Xtlogit Date Tue, 15 Feb 2011 12:07:42 +0100

```<>

Dear Emmanuel,

```
fixed effect logit is calculated via clogit.ado. Here, the fixed effect is not estimated explicitly, but is "conditioned out". Read clogit.ado's help doc for a first impression.
```
best

Klaus Pforr

Am 15.02.2011 12:01, schrieb Milet Emmanuel:
```
```Dear statalist users,

I have a simple interrogation regarding the Xtlogit procedure:
```
what does stata actually do with the fixed effect ? In an xtreg it subtracts the mean, but I could not find in the xtlogit.ado any clue about what's going on here.
```
```
I wonder since when I run the two following estimations, my results are somehow different:
```
Estimation 1: xtlogit y x1 x2, fe i(panel_var)
Estimation 2: xi: logit x x1 x2 i.panel_var

```
I would rather trust the Estimation 2, but I wonder why the results are different.
```
Here is an abstract of the results, for you to see the differences:

With the Xtlogit:
```
------------------------------------------------------------------------------ xstatus | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- lgdpc | 1.135492 .1741228 6.52 0.000 .794218 1.476767 lpop | .9073863 .0665109 13.64 0.000 .7770274 1.037745 ldist | -.9110466 .0912266 -9.99 0.000 -1.089848 -.7322458
```
With the Logit including fixed-effects:
```
------------------------------------------------------------------------------ xstatus | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- lgdpc | 1.176038 .178538 6.59 0.000 .8261099 1.525966 lpop | .9565665 .0688508 13.89 0.000 .8216214 1.091512 ldist | -.9724132 .093985 -10.35 0.000 -1.15662 -.7882059
```

Thanks,

Emmanuel Milet
CEPII, Paris, France
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```
```

--
__________________________________

Klaus Pforr
MZES AB - A
Universität Mannheim
D - 68131 Mannheim
Tel:  +49-621-181 2801 (nachmittags)
fax:  +49-621-181 2803
URL:  http://www.mzes.uni-mannheim.de

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```