EPO forward cit low coverage?

[Damian_TR]

Dear Forum, I want to analyze at the regional level the forward citations for european regions (I am planning to use Postal codes and aggregate them to NUTS3 level), but first I need to work at the patent (applicant) level to check for self cit (if a firm in the cited patent is the same in the citing patent). I am working with EPO patents coming from OECD Reg Pat (202202_EPO_CITATIONS.txt).
I see that the coverage for citing EPO patents is complete (nearly 3.8 million EPO patents citing other patents not exclusively from EPO), but when looking at cited EPO patents (for forward cit) I see only 892,089 cited EPO patents (and of course, these patents are only cited by other EPO patents only). So, the coverage for computing forward cit for EPO european patents is very low in comparison with backward cit. And even worse, you can only see if a EPO cited patent, is cited by another EPO patent (but you do not know if an EPO patent is cited by other authorities patent).
Am I missing something here? When I see other papers working with EPO database at regional level and computing forward cit, do they also have this issue (and thus, their coverage is also low)? I mean, do they only compute EPO to EPO forward citation measures?
I will appreciate any advice!

Thanks!

[EPO / EPAL Team]

please forward this question to support@epo.org and indicate PATSTAT in the subject line

[dullard]

I've encountered a similar issue while working with EPO data. From what I've gathered, many researchers do indeed focus on EPO to EPO forward citations due to the same limitation. To improve the coverage, some supplemental EPO data with PATSTAT or other databases that include citations from non-EPO patents. This can help provide a more comprehensive view of forward citations. It might also be worth looking at

[fightchestplate]

Hi there,

I’ve run into a similar issue with patent citation data before. The coverage gap you’re seeing between citing and cited EPO patents is a common challenge. It’s true that EPO-only data can be limited since it doesn’t include citations from other patent offices.

What worked for me was expanding the dataset to include patents from other regions as well. Combining EPO data with citations from sources like the USPTO or JPO helped fill in the gaps and provided a more complete picture of forward citations. Another approach is to look at additional databases or commercial patent analytics tools that might offer more comprehensive citation records.

Many studies do focus on EPO-to-EPO citations due to these limitations, so it’s worth noting that your results might be consistent with other research in this area.

Hope this helps!

Best,