From: "Nick Cox" <[email protected]>
Reply-To: [email protected]
To: <[email protected]>
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
[email protected]
Andr� 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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