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Re: st: dropping dummies variables

From   "ALICE DOBSON" <>
Subject   Re: st: dropping dummies variables
Date   Tue, 30 Aug 2005 07:21:53 -0400

Hi Statalisters,
I have a similar problem. The stata command to create a categorical variable is xi i.variable
I have some very large categorical variables with around 50 categories
When I use a regression command I drag and drop each category to the command line
for instance xtreg sales market1 market2 market 3 .........
In such case I get the estimates
However, when I use the command
xi xtreg sales it just creates the dummies


From: Seb Buechte <>
Subject: Re: st: dropping dummies variables
Date: Tue, 30 Aug 2005 10:02:55 +0200


posting the same mail twice or even three times will not increase the
number of responses. As I pointed out earlier you may have to post
some of your code and some of you data, so someone who wants to can
actually help you.

Kind regards,

On 8/30/05, Federica Demaria <> wrote:
> > Dear all,
> > I have a panel of 7 countries, identified by the variable id. When I run the following regression
> > xi: reg y x1 x2 i.year
> > as expected, Stata omits the first dummy of both the id and year sets of dummies.
> > The strange thing is that it also drops another dummy variable of both the mentioned sets of dummies, but it uses in the estimation the corresponding country and year.
> > Could you please help me in understanding the reason behind this dropping?
> > thank you in advance
> > Federica
> > Department of Economics anad Statistics
> > University of Calabria
> >
> >
> >
> >

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