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| From | Roberto Ferrer <refp16@gmail.com> |
| To | Stata Help <statalist@hsphsun2.harvard.edu> |
| 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 <r05zhang@gmail.com> 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 > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/