Re: Derwent Patent Citation Index: Missing Citations

Steve Reynolds (Stephen.E.Reynolds@usa.dupont.com)
Thu, 12 Aug 1999 14:00:55 -0400

At 08:48 AM 08/11/1999 +0200, J=F6rg Ohms wrote:
>The concept of Derwents Patent Citation Index (DPCI) includes the
>documentation of both cited and citing patents. This means that a given
>citation should be retrieved within the CITED PATENT SEGMENT of a
>younger patent family record and within the the CITING PATENT SEGMENT of
>its own patent family record.
>The european patent EP 877245 cites the german patent DE 4244082. This
>is documented within the CITED PATENT SEGMENT of its own patent family
>record (AN 1998-387103). However, this citation is missing within the
>patent family record of DE 4244082. The CITING PATENT SEGMENT of this
>record simply does not not exsist (AN 1994-218920).
>I am wondering how often such missing citations occur within the DPCI
>file. Has anyone made similar observations or did we find the only bad
>record within the DPCI file?
>
Well Joerg I can't answer that question but I have a couple of
comments on DPCI and will take this opportunity to make them.

Using this file is not as easy as it should be. If you go to
Derwent's webpage there is no way to navigate to any information on
DPCI. If you use the "site search" you can get a minor amount of=20
information on the file. STN provides a massive amount of information
on their website and summary sheet but it is in the form of a dump
of information. There is nothing as informative as an explanation
or example of what is a citeD patent and what is a citinG patent. =20
On the rare occasion someone ask me to search this file I reread what
information is available, get confused, start getting a headache,=20
and throw up my arms and search both fields and spend twice the money.
I would guess most searchers are in a similar dither and just don't use
the file enough to gain enough familiarity to have a similar=20
observation.

Regards,
Steve Reynolds
DuPont