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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: How to generate a cumulative sum (capital stock) |

Date |
Fri, 26 Oct 2007 17:18:08 +0100 |

Austin Nichols has already replied helpfully and you may have solved your problem. I can't comment helpfully on what went wrong here because you don't show us exactly what you typed. My code looks good to me. A difference between Austin's solution and mine is whether you add investment at time 1. Damiano Sorry for my first message (yes, I was vague. There was another message concerning the cumulative sum). I'm writing again because I tried to use your commands in Stata 9.2 but, as for Austin's suggested program, the new "k" column is empty! Could you help me to solve this odd result? > Forgetting the panel aspect for a moment, > > gen K = k > replace K = 0.95 * K[_n-1] + I in 2/l > > That is, you initialise a variable and > then -replace- all the first value. > [_n-1] is Stata's way of referring to > the previous value. > > Now reinserting the panel aspect, you > need to work > > by firm: > > but -by:- won't let you work with -in-. > > gen K = k > bysort firm (year) : replace K = 0.95 * K[_n-1] + I if _n > 1 > > should be closer to what you want. > > If you -tsset-, the solution would be better as > > tsset firm year > gen K = k > by firm: replace K = 0.95 * L.K + I if _n > 1 > > Nick > n.j.cox@durham.ac.uk > > Damiano Rossi > > I need some help to compute a capital stock series from a gross > investment series. My primary problem is that I have to estimate the > initial capital stock (K_0 ) for each firm. As a general rule, it is > used the book value of fixed capital (K) in the first year of data (e.g. > 1996) for each firm. How can I command Stata to consider this first > observation (firm by firm) and then compute a capital stock series, > using a perpetual inventory and a constant rate of depreciation? A > previous post doesn't help me much on this point. These are the data. > > Panl oif 300 firms, 10 years (1996-2006) > k = capital stock > I = capital investment > d [delta] = 0.05 > > The evolution of the real capital stock is: > K_t+i = (1 - d)*K_t+i-1 + I_t+i * * 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/

**References**:**Re: st: How to generate a cumulative sum (capital stock)***From:*west--@libero.it

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