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Re: st: Create a flag (panel data)


From   Roberto Ferrer <[email protected]>
To   Stata Help <[email protected]>
Subject   Re: st: Create a flag (panel data)
Date   Fri, 7 Mar 2014 01:25:25 -0430

I think this will give you what you want, but it will work depending
on the size of your database because -joinby- creates, at least
temporarily, new observations.

*----------------------- begin code --------------------

*clear all
set more off

*----------------------- example data --------------------

input ///
year       str2 firmid    patentID              citedID
1995      "AA"           100001            100002
1995      "AA"           100001            100003
1995      "AA"           100001            100004
1994      "AA"           110001            100002
1994     "AA"           110001            100005
1994     "AA"           110001            120001
1993      "AA"           120001            100006
1993      "AA"           120001            100007
1992      "AA"           130001            100008
1992      "AA"           130001            100009
1991      "AA"           140001            1000010
1991      "AA"           140001            100011
1989     "AA"           140001            100011
1988     "AA"           140001            100011
1995      "BB"           100001            100002
1995      "BB"           100001            100003
1995      "BB"           100001            100004
1994      "BB"           110001            100002
1994     "BB"           110001            100005
1994     "BB"           110001            120001
1993      "BB"           120001            100006
1993      "BB"           120001            100007
1992      "BB"           130001            100008
1992      "BB"           130001            100009
1991      "BB"           140001            1000010
1991      "BB"           140001            100011
end

sort firmid year
list, sepby(firmid)

tempfile main
save "`main'"

*---------------------- what you want ? -------------------------

rename (year patentID citedID) =0
joinby firmid using "`main'"

sort firmid year0 year
by firmid: drop if year0 < year
by firmid: drop if (year0 - year) > 4

by firmid: gen flag = (citedID0 == patentID | citedID0 == citedID) &
(year0 != year)

drop year patentID citedID
rename *0 *

collapse (sum) flag, by(year firmid patentID citedID)

sort firmid year
replace flag = (flag > 0)
list, sepby(firmid)

*---------------------- end code ----------------------------

Insert -list- anywhere you like, to see what's going on.

On Thu, Mar 6, 2014 at 10:07 PM, R Zhang <[email protected]> wrote:
> Dear Statalisters,
>
> I have the following panel data (only provided a small number of observations)
>
> PatentID: is the identification number for company AA's patent,
> citedID is the identification number of a patent that was cited by the
> focal patent. I want to generate a dummy that flags the citedID under
> the following condition:
>
> citedID=1 if this patent (e.g. 1995 100002 was firm AA's own patent
> filed over the past 5 years, Or 100002 was a patent that was cited by
> firm AA over the past 5 years).  Could you suggest a good way of doing
> this?  Thanks !!!
>
> Year       firmid    patentID              citedID
>
> 1995      AA           100001            100002
>
> 1995      AA           100001            100003
>
> 1995      AA           100001            100004
>
> 1994      AA           110001            100002
>
> 1994     AA           110001            100005
>
> 1994     AA           110001            120001
>
> 1993      AA           120001            100006
>
> 1993      AA           120001            100007
>
> 1992      AA           130001            100008
>
> 1992      AA           130001            100009
>
> 1991      AA           140001            1000010
>
> 1991      AA           140001            100011
>
> -Rochelle
>
> *
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