Forward and backward citation for a number of Patents

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Posts: 13
Joined: Thu Nov 12, 2015 9:59 am

Forward and backward citation for a number of Patents

Post by torben » Thu Jan 28, 2016 1:07 pm

i'm using the online version of Patstat (autumn 2015).

I want to count the number of forward and backward citations of a previous defined list of patents. Therefor I searched this forum for a solution, but didn't find something.

To get the number of foward citation, I think I could use this query:

SELECT DISTINCT tls201_appln.appln_id, nb_citing_docdb_fam
From tls201_appln
WHERE tls201_appln.appln_id in (LIST OF PATENTS)

The only problem is, that i want to constrain the period of forward citation on max 5 years.

I didn't know a solution for the backward citations. This is a first attempt of mine:

SELECT Distinct tls201_appln.appln_id, count (distinct tls212_citation.cited_pat_publn_id)
From tls201_appln
JOIN tls211_pat_publn on tls201_appln.appln_id = tls211_pat_publn.appln_id
JOIN tls212_citation on tls211_pat_publn.pat_publn_id = tls212_citation.pat_publn_id

WHERE tls201_appln.appln_id in (LIST OF PATENTS)
Group by tls201_appln.appln_id
order by tls201_appln.appln_id

Can I use these querys to get the number of forward and backward citations?

Geert Boedt
Posts: 178
Joined: Tue Oct 19, 2004 10:36 am
Location: Vienna

Re: Forward and backward citation for a number of Patents

Post by Geert Boedt » Fri Jan 29, 2016 3:12 pm

Hello Torben,

the pre-calculated attribute nb_citing_docdb_fam does not take into account any limitations on years, category or origin of the citations. It is a simple count based on the relations defined in the tls212_citation table between publications. Cited or citing (or backward & forward) citations are defined within the same relation because if A cites B (forward) then B is cited by A (backward).
If you want to establish a time window limit between the citations then you will need to compare dates.
The most obvious choice is the compare the publication date from the cited publication with the citing publication. An example of such approach (using DE publications citing EP publications) is explained in this document : ... ies_en.pdf If you download the "WIND" test database, then you will find the query under query8.
Below is another approach using "datediff" . "Un-comment" the datediff condition in the where clause and you will see the difference.

SELECT cited_publication.publn_auth cited_publn_auth
,cited_publication.publn_nr cited_publn_nr
,cited_publication.publn_kind cited_publn_kind
,cited_publication.publn_date cited_publn_date
,citing_publn.publn_auth citing_publn_auth
,citing_publn.publn_nr citing_publn_nr
,citing_publn.publn_kind citing_publn_kind
,citing_publn.publn_date citing_publn_date
,DATEDIFF (day, cited_publication.publn_date, citing_publn.publn_date) datedifference --difference publication dates.
FROM tls211_pat_publn cited_publication join tls212_citation on cited_publication.pat_publn_id = tls212_citation.cited_pat_publn_id
join tls211_pat_publn citing_publn on tls212_citation.pat_publn_id = citing_publn.pat_publn_id
where cited_publication.appln_id = 1 -- and DATEDIFF (day, cited_publication.publn_date, citing_publn.publn_date)< 1825 -- 1825 = 5*365 days = 5 year
order by citing_publn.publn_date

It becomes more complicated if you want to do a family-family citation count because the cited and citing families have a number of applications, which in their turn have a number of publications, all with different dates. My approach would be to compare the dates from each citation pair (as above) and simply flag all family pairs that have at least one citation pair that matches the time window. This solution requires a locally installed PATSTAT database (or an extraction).
Best regards,

Geert Boedt
PATSTAT support
Business Use of Patent Information
EPO Vienna

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