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 <[email protected]>
To: [email protected]
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
> >
> >
> >
> *
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*
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