RE: st: RE: Cumulative Sum by groups

["Alexander Nervedi" <alexnerdy@hotmail.com>]

I get the error  message "time-series  operators not allowed".  i have tsset 
set - i dont think thats necessary to use this is it ?

-AN


> From: "Nick Cox" <n.j.cox@durham.ac.uk>
> Reply-To: statalist@hsphsun2.harvard.edu
> To: <statalist@hsphsun2.harvard.edu>
> Subject: st: RE: Cumulative Sum by groups
> Date: Fri, 22 Apr 2005 15:18:32 +0100
>
> bysort ID (year) : gen cusum = _N - _n + 1
>
> Nick
> n.j.cox@durham.ac.uk
>
> Alexander Nervedi
>
> > I am looking to implement a group level cumulative sum that
> > starts counting
> > backwards. Any suggestions on how to go about this would be
> > really useful
> >
> > data example:
> > ID  year  num   cusum
> > 1    90      1       2
> > 1    91      1       1
> > 2    90      1       4
> > 2    91      1       3
> > 2    92      1       2
> > 2    93      1       1
> > 3    90      1       1
> > 4    90      1       2
> > 4    90      1       1
> > ...
> >
> > I have variables ID year and num, and am trying to create cusum
>
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