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st: RE: problem with commands
From
"Vassilopoulos Achilleas" <[email protected]>
To
<[email protected]>
Subject
st: RE: problem with commands
Date
Tue, 7 Sep 2010 23:52:57 +0300
Sorry, I've just found out that some lines in my previous post did not
appeared separated so I thought I should repost.
I think this is what you're looking for :
cd "YOUR_DIRECTORY"
gen firstsic_sub=int(sic_sub/100)
gen firstsic_moth=int(sic_mother/100)
gen twosic_sub=int(sic_sub/10)
gen twosic_moth=int(sic_mother/10)
capture erase new.dta
tempname new
postfile `new' str10 id_mother year double diver using new
levelsof year_inc_sub, local(levels)
foreach y of local levels {
count if (year_inc_sub<=`y') & (firstsic_moth!=firstsic_sub)
scalar digit=r(N)
count if year_inc_sub<=`y'
scalar total=r(N)
scalar a=scalar(digit)*3/scalar(total)
count if (year_inc_sub<=`y') & (firstsic_moth==firstsic_sub)
scalar digit2=r(N)
scalar b=scalar(digit2)*2/scalar(total)
count if (year_inc_sub<=`y') & (twosic_moth==twosic_sub)
scalar digit3=r(N)
scalar c=scalar(digit3)*1/scalar(total)
scalar all=scalar(a)+scalar(b)+scalar(c)
post `new' ("X") (`y') (scalar(all))
scalar drop all digit total
}
postclose `new'
use new, clear
sort year
Hope this helps,
_____________ - _______________
Achilleas Vassilopoulos
Agricultural University of Athens,
Dept. of Agricultural Economics and Rural Development, Lab. of Political
Economy and European Integration.
Iera Odos 75, 11855, Athens, Greece
Tel: (+30) 210-5294726
Fax: (+30) 2105294786
Email : [email protected]
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of ???s???a
G?a?????p?????
Sent: 07 September, 2010 13:49
To: [email protected]
Subject: st: problem with commands
Dear Statalisters,
I have a data set consisting of a number of companies which are all
subsidiaries of the same company X. The following variables describe
each of these companies and their mother company:
1) "id_mother", the identity of the mother company
2) "id_sub", the identity of the subsidiary company
3) "year_inc_sub", year of incorporation of the subsidiary
4) "SIC_mother", a 3-digit industry classification code for the mother
5) "SIC_sub", a 3-digit industry classification code for the subsidiary
The dataset looks like this:
id_mother sic_mother id_sub sic_sub year_inc_sub
X 731 JP0JPN 738
1982
X 731 JP680JPN 737
2002
X 731 JP0JPN 899
2002
X 731 JP0JPN 355
1953
X 731 JPJPN 355
2001
X 731 JPN 502
1972
X 731 JPJPN 357
1960
Based on this information I want to create a new dataset with a
time-series structure, which will refer to the mother company "X" for
the period 1990-2005. In the new dataset I want to have the following
variables:
1) "id_mother", as above;
2) "year", the year of the observation;
3) "diversification", a new variable whose estimation I explain below.
The diversification variable should be created under the following logic:
For observation in year 1990 the value of diversification should be
the sum of a, b, and c below:
a) take the total number of subsidiary companies which were
incorporated in 1990 or earlier whose 1st digit of sic_sub is
different than the 1st digit of sic_mother and multiply them by 3;
divide this number by the total number of companies which where
incorporated in 1990 or earlier (in the example, the total number of
companies existing in 1990 is 4)
b) take the total number of subsidiary companies which were
incorporated in 1990 or earlier for which only the 1st digit of their
sic_sub is the same as the 1st digit of sic_mother and multiply them
by 2; divide this number by the total number of companies which where
incorporated in 1990 or earlier
c) take the total number of subsidiary companies which were
incorporated in 1990 or earlier, whose 1st and 2nd digits of sic_sub
are the same as the 1st and 2nd digits of sic_mother but they differ
in the 3rd digit, and multiply them by 1, divide this number by the
total number of companies which where incorporated in 1990 or earlier
The same logic should apply for the observations for years 1991-2005
The expected dataset should look like this:
id_mother year diversification
X 1990 a+b+c when subsidiaries incorporated
earlier than or equal to 1990
X 1991 a+b+c when subsidiaries incorporated
earlier than or equal to 1991
X 1992 a+b+c when subsidiaries incorporated earlier
than or equal to 1992
X
............................................................................
................................
X 2005 a+b+c when subsidiaries incorporated earlier
than or equal to 2005
- Hide quoted text -
Thank you in advance.
Chrysa
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