RE: st: Binary Variables

["Martin Weiss" <martin.weiss1@gmx.de>]

<>

" Alternatively, why not fit your model using -xtreg-"


Natalie did report her frustration re -xtreg, fe- earlier:
http://www.hsph.harvard.edu/cgi-bin/lwgate/STATALIST/archives/statalist.1006
/date/article-119.html


HTH
Martin


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Clive Nicholas
Sent: Donnerstag, 3. Juni 2010 00:38
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Binary Variables

Natalie Trapp wrote:

> I have a problem concerning Dummy Variables.
>
> I use a Dummy Variable for 150 regions within the EU27. When I regress the
> model, I use one region as a reference group, but Stata still
automatically
> omits four to five more regions. Is it maybe because the regions are too
> similar in their characteristics so that I have to build groups of similar
> regions? Or is there another way how I can do the regression with all
> regions of interest?

Your later post shows that you are using -reg-. But why not use -areg-
with the -absorb()- option? In that option you would insert one,
simple categorical regional variable.

Alternatively, why not fit your model using -xtreg- with the -i()- and
-fe- options? Your regional variable slots into the -i()- option.

The coefficients and standard errors are the same under both
approaches, as you can see at

http://www.stata.com/support/faqs/stat/xtreg.html

but your model R-squared will differ, as explained at

http://www.stata.com/support/faqs/stat/xtr2.html

-- 
Clive Nicholas

[Please DO NOT mail me personally here, but at
<clivenicholas@hotmail.com>. Please respond to contributions I make in
a list thread here. Thanks!]

"My colleagues in the social sciences talk a great deal about
methodology. I prefer to call it style." -- Freeman J. Dyson.
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/