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Forward citations and coverage

Posted: Fri May 29, 2020 10:56 am
by alexis
Hello everyone,

I am using PATSTAT Online and I am interested in the number of citations received by Finnish patents (national office) 5 years after the grant date. I wrote a query for that and I have couple of questions

1) The following query seems to work but I would like to double check with you if it is correct.

Code: Select all

SELECT  t1.appln_id, COUNT(distinct t4.pat_publn_id) AS fcitation
FROM tls201_appln t1
tls211_pat_publn t2
ON t1.appln_id = t2.appln_id 
 (SELECT appln_id, publn_date
 FROM tls211_pat_publn 
 WHERE publn_first_grant = 'Y' ) t3
 ON t1.appln_id = t3.appln_id
tls212_citation t4 ON t2.pat_publn_id = t4.cited_pat_publn_id
INNER JOIN tls211_pat_publn t5
ON t5.pat_publn_id = t4.pat_publn_id
 t1.appln_auth = 'FI' AND 
year(t3.publn_date) >= 1975
AND year(t3.publn_date)+5 >= year(t5.publn_date)
GROUP BY t1.appln_id
ORDER BY fcitation DESC
2) It seems that the coverage of citations for national offices is not great especially for Finland (cf Overview of citation data in the EPO’s citation database). Is it correct to interpret that the number of citations received by Finnish patents is underestimated because of the lack of information in PATSTAT regarding citations from patents granted in Finland? (in my query t5.publn_auth = 'FI' )

3) Is there any information on the reliability of the citations coverage per country? Which country would be more complete? Is the citations coverage for European Patents or PCT better?

Thank you.


Re: Forward citations and coverage

Posted: Wed Jun 03, 2020 12:09 pm
by EPO / PATSTAT Support
Hello Alexis,
On 1) your query looks fine. When I do such counts, I would take just the first 2 applications, and manually check if the forward citations are effectively counted as you want them.
On 2) coverage of the citation information is documented in the REFI publication which you can find at this link: ... gular.html It is correct that we do not receive citation information for patent applications published in Finland. But forward citations are not dependant from the Finish search reports, other offices can (and do ) cite Finish applications as your query illustrates. As a result; what you will not find are Finish applications citing other Finish applications.
On 3): citation information for EP and PCT (WO) should be complete.
When in doubt about coverage and completeness, one can always write a little query to find out what the last publications were in PATSTAT for which we have citation data. Something like this (which shows that the latest WO publication having citations was published on 2020-02-13 for PATSTAT 2020a).

Code: Select all

SELECT TOP 100 citing.appln_id, citing.publn_auth, citing.publn_nr, citing.publn_kind, citing.publn_date, tls212_citation.*,
cited.publn_auth, cited.publn_nr, cited.publn_kind, cited.publn_date, tls214_npl_publn.*
  FROM tls211_pat_publn citing join tls212_citation on citing.pat_publn_id = tls212_citation.pat_publn_id
  join tls211_pat_publn cited on tls212_citation.cited_pat_publn_id = cited.pat_publn_id
  join tls214_npl_publn on tls212_citation.cited_npl_publn_id = tls214_npl_publn.npl_publn_id 
  join tls201_appln citing_app on citing.appln_id = citing_app.appln_id
  where citing_app.appln_auth = 'WO'
order by citing.publn_date desc, citing.appln_id

Re: Forward citations and coverage

Posted: Fri Jun 05, 2020 9:58 am
by alexis
Thank you very much for your great work!