Johannes, thanks for this.
Eva Poen gave me this code,
gen other = Result2 != "TM Ei-svar"
bysort Id (Commdate) : replace other = sum(other)
by Id (Commdate) : gen dummy = other[_N]==0
drop other
which works fine.
I tried your code as well, but it does not replicate the above solution, most likely because my statement of the problem was unclear. Sorry about that.
I am still puzzled about why my code did not work. I thought that I could use _N to look forward and _N-1 to look backwards, within Id and Commdate.
Anyway, problem solved. Thanks for the help.
Best wishes,
Alexander Severinsen
-----Opprinnelig melding-----
Fra: [email protected] [mailto:[email protected]] På vegne av Johannes Geyer
Sendt: 18. mars 2009 11:28
Til: [email protected]
Emne: Re: st: bys and [_N] within replace
you could do the following:
bys Id Result2: gen helpvar = _n == 1
egen kun_eisvar = total(helpvar), by(Id)
replace kun_eisvar = kun_eisvar == 1
drop helpvar
Hope this helps,
Johannes
----------------------
Johannes Geyer
Deutsches Institut für Wirtschaftsforschung (DIW Berlin)
German Institute for Economic Research
Department of Public Economics
DIW Berlin
Mohrenstraße 58
10117 Berlin
Tel: +49-30-89789-258
[email protected] schrieb am 18/03/2009 11:05:24:
> I have the following panel.
>
>
> Id Commdate Result2
> 400 05may2008 TM FAILURE
> 400 29may2008 DM FAILURE
> 400 05oct2008 TM Ei-svar
> 400 27oct2008 TM Ei-svar
> 400 30nov2008 TM Ei-svar
> 400 04jan2009 TM Ei-svar
>
> I would like to generate a binary variable that equals 1 if a
> category "TM Ei-svar" within result2 occurs. But I only want this to
> happen if no other category in Result2 is present within Id, either
> onwards are backwards in time (Commdate). Nick Cox and Martin Weiss
> gave excellent advice on an earlier related problem pointing me to
> 'bys' and using [_N] within replace statements. Nick also refered me
> to further free 'by' tricks at
>
> http://www.stata-journal.com/sjpdf.html?articlenum=pr0004
>
> However, I am still unable to solve the above problem. I tried
>
> gen kun_eisvar=0
> bys Id (Commdate):replace kun_eisvar=1 if ///
> (result2=="TM Ei-svar"& ///
> result2[_N]!="TM FAILURE"&result2[_N-1]!="TM FAILURE"& ///
> result2[_N]!="TM SUCCESS"&result2[_N-1]!="TM SUCCESS"& ///
> result2[_N]!="SUCCESS DM SMS 1999"&result2[_N-1]!="SUCCESS DM
SMS1999"& ///
> result2[_N]!="DM SUCCESS NY BIND"&result2[_N-1]!="DM SUCCESS NY
BIND"& ///
> result2[_N]!="DM SUCCESS"&result2[_N-1]!="DM SUCCESS"& ///
> result2[_N]!="DM FAILURE"&result2[_N-1]!="DM FAILURE")
>
> though, this does not work. See an example below.
>
> Id Commdate Result2 kun_eisvar
> 400 05may2008 TM FAILURE 0
> 400 29may2008 DM FAILURE 0
> 400 05oct2008 TM Ei-svar 1
> 400 27oct2008 TM Ei-svar 1
> 400 30nov2008 TM Ei-svar 1
> 400 04jan2009 TM Ei-svar 1
>
> Because Result2 has other categories than 'TM Ei-svar' for Id=400
> this observation should not equal 1.
>
> Any advice on where I went wrong is appreciated.
>
>
> Best wishes,
> Alexander
>
>
>
>
>
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