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Re: RE: st: Again-Unique Case ID in Large Panel


From   smerryman@kc.rr.com
To   statalist@hsphsun2.harvard.edu
Subject   Re: RE: st: Again-Unique Case ID in Large Panel
Date   Wed, 04 Aug 2004 13:25:51 -0500

Yes, Nick has it.  If the width() option is not wide enough -xtdes- will report
 non-unique id*time values (example below).

What is the purpose of the width() option?

Scott


 
. webuse grunfeld

. xtdes,   width(3)

 company:  1, 2, ..., 10                                     n =         10
    year:  1935, 1936, ..., 1954                             T =         20
           Delta(year) = 9; int((1954-1935)/9) + 1 = 3
           (company*year does not uniquely identify observations)

. xtdes

 company:  1, 2, ..., 10                                     n =         10
    year:  1935, 1936, ..., 1954                             T =         20
           Delta(year) = 1; (1954-1935)+1 = 20
           (company*year uniquely identifies each observation)




----- Original Message -----
From: Nick Cox <n.j.cox@durham.ac.uk>
Date: Wednesday, August 4, 2004 12:48 pm
Subject: RE: st: Again-Unique Case ID in Large Panel

> I got it, I think. You need to play
> around with the -width()- option in 
> -xtdes-. I surmise that the default
> is not big enough for your data. 
> 
> (I was predisposed to think the blame
> would lie with -xtdes-.) 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 


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