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Re: st: Problem with xi (Stata 11)
From
Walter Garcia-Fontes <[email protected]>
To
[email protected]
Subject
Re: st: Problem with xi (Stata 11)
Date
Wed, 2 Jun 2010 15:34:47 +0200
It seems a problem that I'm only able to reproduce in my machine, from
a fresh started stata and entering the following commands:
webuse set http://puna.upf.edu
webuse data/data
xi i.COUNTRY
ta COUNTRY _ICOUNTRY_56, nol
Country |
code | COUNTRY==56
3-digit | 0 1 | Total
-----------+----------------------+----------
40 | 4,927 0 | 4,927
56 | 265 8,592 | 8,857
203 | 5,932 0 | 5,932
208 | 4,532 0 | 4,532
233 | 4,865 0 | 4,865
246 | 4,714 0 | 4,714
250 | 4,716 0 | 4,716
276 | 4,891 0 | 4,891
300 | 4,873 0 | 4,873
348 | 4,490 0 | 4,490
372 | 4,444 141 | 4,585
380 | 21,773 0 | 21,773
-----------+----------------------+----------
Total | 70,422 8,733 | 79,155
I get this both in updated Stata 10 and Stata 11.
My machine is a Dell Precision 690 running Ubuntu Gnu-Linux 10.04.
I tried it also at a Sun server running Solaris and I can't reproduce
under Stata 10 (no Stata 11 there yet).
So it seems some combination of a particular machine precision and the
xi command.
tab COUNTRY, gen(_ICOUNTRY)
works perfectly on the other hand.
Walter
* Martin Weiss [02/06/10 15:10]:
>
> <>
>
>
> " Stata 11 users are encouraged officially to use factor variables"
>
>
> Walter may have a point, though, if all he wants is to use -xi- as a
> standalone command, to generate dummies for a categorical variable. -tab,
> gen()- may be an alternative.
>
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: [email protected]
> [mailto:[email protected]] Im Auftrag von Roger Newson
> Gesendet: Mittwoch, 2. Juni 2010 15:01
> An: [email protected]
> Betreff: Re: st: Problem with xi (Stata 11)
>
> I don't know what exactly is going on in your case. However, I do know
> that Stata 11 users are encouraged officially to use factor variables
> instead of -xi-, although -xi- should still work (and has done so for me
> so far).
>
> Best wishes
>
> Roger
>
>
> Roger B Newson BSc MSc DPhil
> Lecturer in Medical Statistics
> Respiratory Epidemiology and Public Health Group
> National Heart and Lung Institute
> Imperial College London
> Royal Brompton Campus
> Room 33, Emmanuel Kaye Building
> 1B Manresa Road
> London SW3 6LR
> UNITED KINGDOM
> Tel: +44 (0)20 7352 8121 ext 3381
> Fax: +44 (0)20 7351 8322
> Email: [email protected]
> Web page: http://www.imperial.ac.uk/nhli/r.newson/
> Departmental Web page:
> http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgene
> tics/reph/
>
> Opinions expressed are those of the author, not of the institution.
>
> On 02/06/2010 13:47, Walter Garcia-Fontes wrote:
> > I have a problem with the "xi" command in Stata 11 (completely updated
> > as of today). I tried to create a dataset as simple as possible to
> > reproduce the problem, which can be accessed from my server. In the
> > dataset there is a single variable called COUNTRY with numeric codes
> > for each country and labels identifying the country.
> >
> > There are 12 different values for COUNTRY (12 different countries) and
> > 79155 observations with a variable number of observations for each
> country.
> > To reproduce:
> >
> > webuse set http://puna.upf.edu
> > webuse data/data.dta
> > xi i.COUNTRY
> >
> > Stata creates variables _ICOUNTRY_n as it should, where n are the
> > different codes for the 12 countries, omitting the country with the
> > smallest code.
> >
> > The problem is that some of the values of _ICOUNTRY are 0 when they
> > shouldn't be, for instance I have cases where _ICOUNTRY_56 = 0 but
> > COUNTRY = 56. This happens randomly for a few cases and I've looked at
> > it from all angles but couldn't figure out what is going on.
> >
> > If I reduce the number of variables or the number of observations the
> > problem disappears at some point, can't tell exactly when, so I'm
> > providing the smallest example I could build.
> >
> > Walter
> >
> *
> * 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/
--
Walter Garcia-Fontes
mailto: [email protected] - http://puna.upf.edu
Departament d'Economia i Empresa - http://www.econ.upf.edu
Universitat Pompeu Fabra
Ramon Trias Fargas 25-27, 08005 Barcelona, Spain
Tel. +34 93 542 2722 - Fax. +34 93 542 1746
*
* For searches and help try:
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