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RE: st: RE: cumulative sum with depreciation


From   André Paul <hcpats@hotmail.fr>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: RE: cumulative sum with depreciation
Date   Sun, 19 Mar 2006 20:19:53 +0100

Thanks, it is easier than what I imagined...
André


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 with depreciation
Date: Sun, 19 Mar 2006 19:10:20 -0000

bysort Firm (year) : gen S_t = 0
by firm : replace S_t = 0.85 * S_t[_n-1] + R_t if _n > 1

Nick
n.j.cox@durham.ac.uk

André Paul

> I would like to build a stock variable with declining balance
> depreciation:
>
> S_t=0.85*S_t-1 + R_t
> (the initial value is always 0)
>
> The data (an unbalanced panel) looks like:
>
> Firm	year	R
> 2	1980	0
> 2	1981	1
> 2	1982	0
> 2	1983	7
> 2	1984	9
> 2	1985	4
> 2	1986	3
> 3	1994	0
> 3	1995	0
> 3	1996	0
> 3	1997	1
> 3	1998	0
> .
> .
> .
>
> But I couldn't find a way to build the variable "S", can
> anybody help me?

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