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?
*
* 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/
