Re: st: superposed rolled windows

[Jeph Herrin <jherrin@flyingbuttress.net>]

That's why you drop if profits2==.; to get rid of obs
where there is no future window.

irodriguez wrote:
> But i dont want all the observations
> for example if a firm has observations for 1990-2004 the new database will
> have observations for 1990-2002. In the same way for a firm with data for
> 1990-1995 will have observations for 1990-1993
> Thanks
>
> -----Original Message-----
> From: Jeph Herrin <junk@spandrel.net>
> To: statalist@hsphsun2.harvard.edu
> Date: Tue, 27 Jun 2006 10:17:23 -0400
> Subject: Re: st: superposed rolled windows
>
> > Try
> >
> >   gen profits1=profits
> >   bys firms (years): gen profits2=profits[_n+1]
> >   bys firms (years): gen profits3=profits[_n+2]
> >   drop if profit2==.
> >
> > HTH,
> > Jeph
> >
> >
> > irodriguez wrote:
> > > statalisters
> > > i need to generate some columns data in excel I think I could
> > calculate
> > > them in stata
> > > I have a panel data with firms, and profits for the period 1990/2004
> > No
> > > all the firms have the same period of data
> > > I need to calculate others 4 columns for profit
> > > superposing a rolling period window of 3 periods.
> > > Example:
> > > original data base
> > > Firms    Years   Profits
> > > firm 1     1990     7
> > > firm 1      1991     9
> > > firm 1      1992      2
> > > firm 1      1993       6
> > > firm 1       1994      5
> > > firm 1       1995     4
> > > firm 2      1990      3
> > > firm 2      1991      2
> > > firm 2      1992      1
> > > firm 2       1993     3
> > > ...
> > >
> > > New data base
> > > Firms    Years   Profits1    Profit2   Profit3
> > > firm 1     1990     7                9         2
> > > firm 1      1991     9               2         6
> > > firm 1      1992      2              6         5
> > > firm 1      1993       6            5          4
> > > firm 2      1990      3             2           1
> > > firm 2      1991      2              1          3
> > >
> > > How can I do it
> > > Thanks
> > *
> > *   For searches and help try:
> > *   http://www.stata.com/support/faqs/res/findit.html
> > *   http://www.stata.com/support/statalist/faq
> > *   http://www.ats.ucla.edu/stat/stata/
>
> *
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*
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