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Last seen: 09/05/2022 - 15:38
Joined: 06/17/2022 - 09:59
Why a patent can cite another patent filed after it?

Dear PV team,

I'm using uspatentcitation.tsv dataset. I found a weird pattern: a patent A can cite another patent B whose application is filed after the focal patent(patent A). For instance, patent 3943789 cite patent 5857301, 3943789 is filed on October 3, 1974, and granted onMarch 16, 1976. 5857301 is filed on November 5, 1996 and granted on January 12, 1999. How could 3943789 cite 5857301 if 5857301 does not exist before October 3, 1974/March 16, 1976 ?

Last seen: 09/22/2023 - 22:51
Joined: 11/14/2017 - 22:15
it is a mistake


You are right, it shouldn't be possible.  It looks like it is a mistake in the USPTO's data that the patentsview database and download files are built from.    The reference in 3943789  is to 5857301, December 1974, Hanks et al. but if we look up 5857301 we find a single inventor Fujita and it was issued in 1999.  If we guess that the first digit should be a 3 and look up 3857301 we find the first of many inventors is Hanks, so Hanks et al and it was issued in December 1974.

Google patents also shows 3943789 referencing 5857301

I hope this helps,
Russ Alllen

Last seen: 09/14/2022 - 07:35
Joined: 09/14/2022 - 07:34
interesting information

interesting information

Last seen: 09/22/2023 - 22:51
Joined: 11/14/2017 - 22:15
the data needs cleaning

I guess it's like any big data set and could use a little cleaning!  I've seen problems where the D was left off the citation of a design patent, where there is an additional digit added or two digits were interchanged.  To me it looks like the equivalent of typos, as if the data was originally entered by hand.   Here's a partial list:

4,291,663 references 368307of
D395,002 references DRe21900
D403,584 references ReD9674
5,013,477 references SN53778

It probably wouldn't be hard to check for cases where the cited dates and patent numbers don't make sense.  There are tables like this one that show the first patent numbers issued per year.  It wouldn't find subtle errors but it would find the glaring ones, like the one that you found.