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Re: st: creating a balanced panel from an unbalanced panel


From   "Vladimir Vakhitov" <vvakhitov@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: creating a balanced panel from an unbalanced panel
Date   Fri, 28 Mar 2008 16:37:28 -0400

Thank you, Austin, for correcting me. It should be _N indeed.
Vladimir


2008/3/28, Austin Nichols <austinnichols@gmail.com>:
> Vladimir Vakhitov <vvakhitov@gmail.com> and Jeremy Page <miahpage@gmail.com>:
>  The solution below does not give the desired result, but substitute _N
>  for _n and it does.  Or in one:
>   bys id: g balanced = (_N==7)
>
>  However, observations may exist and yet contain missing values and
>  therefore be excluded from the regression.  Thus you need something
>  more like
>   qui xtreg y x, i(id) fe
>   g ok=e(sample)
>   egen sumok=total(ok), by(id)
>   su sumok, meanonly
>   g allok=(sumok==r(max))
>   xtreg y x if allok==1, i(id) fe
>
>
>  On Fri, Mar 28, 2008 at 3:20 PM, Vladimir Vakhitov <vvakhitov@gmail.com> wrote:
>  > Hi Jeremy,
>  >
>  >  I would use a simple trick (ID is your panel variable):
>  >
>  >  tempvar q
>  >  bysort id: gen `q' = _n
>  >  gen byte balanced = 0
>  >  replace balanced = 1 if `q'==7
>  >
>  >  Vladimir.
>  >
>  >  2008/3/28, Jeremy Page <miahpage@gmail.com>:
>
> >  >  I have an unbalanced panel of seven period and I would like to be able
>  >  >  to make a subset of a balanced panel.  I have created dummy variables
>  >  >  (T1-T7) for each of the time periods as well as a continuous variable
>  >  >  labeled time (1-7).  I would like to create another dummy variable to
>  >  >  use in the "if" qualifier of a regression which would be "balanced=1"
>  >  >  if there are observations in all 7 periods.
>
> *
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>


-- 
__________________
Volodymyr Vakhitov
vvakhitov@gmail.com
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