Classification Coverage

Here you can post your opinions, ask questions and share experiences on the PATSTAT product line. Please always indicate the PATSTAT edition (e.g. 2015 Autumn Edition) and the database (e.g. PATSTAT Online, MySQL, MS SQL Server, ...) you are using.
Post Reply

Posts: 4
Joined: Wed Jan 20, 2016 11:52 pm

Classification Coverage

Post by DBCerigo » Tue Feb 09, 2016 10:04 pm

Using the 2015 Spring Edition, and SQLite for initial querying then Python (pandas) for analysis.

We are using patent data to investigate innovation generally.

As a preliminary check we plotted the fractional coverage of patents with IPC and CPC classifications by year within the data base.


We were initially slightly surprised by the lack of CPC coverage.
We hoped someone may be able to comment on this. Specifically with regard to:

- it was our understanding that CPC was becoming the dominant system
- why was the CPC required if IPC was already in place and served the purpose?
- are backwards reclassifications/classifications into other systems carried out by national offices or by the EPO?

- on reflection, the majority of the patents that are not from the EU/US only occur in the database in the most recent years, assumedly these are the patents which are not CPC classified and thus bring down the covered fraction (this is corroborated by looking gross numbers for the CPC coverages of patents from authorities not in US/EU countries e.g NOT IN ('US', 'GB', 'DE', 'FR'))

Thanks for you input.

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

Re: Classification Coverage

Post by Geert Boedt » Tue Mar 08, 2016 3:15 pm

The CPC scheme is largely built on the former European CLAssification (ECLA), a classification system itself based on the IPC, but including a large number of further subdivisions in comparison with the IPC. The subdivisions (70 000) offered by the IPC were not deemed sufficient for our examiners to efficiently conduct the prior art searches needed in the patent granting process. Therefore the creation of a much more granular and focussed scheme, ECLA, followed by the CPC in 2013, which now contains about 260.000 subdivisions.
Classification in the IPC is obligatory for all patent offices in the world which are party to the Strasbourg agreement (1972). Though the EPO is not as such party to this agreement due to its multi-national nature, its publications are nevertheless classified in the IPC (Rule 8 EPC). ... /e/r8.html

CPC classifications are now also being applied by some of the largest patent offices around the world to their own publications.

Going back to your questions:

• IPC classifications before 1971 were generated by the EPO as far as possible by mapping the ECLA or European Classification system to the IPC one in the course of the DocDB switch-over in preparation for the IPC reform (2006). This is why IPC and CPC match in the graph from 1920 to 1970.

• After 1970 (when the IPC was created), almost 100% of patents are classified in the IPC by the issuing patent offices themselves. In this period, also the Asian offices became very active in patenting. Japan was first, followed recently by Korea and China. Only around 20% of these documents are currently classified in CPC (the EPO is systematically classifying in the CPC all families including a family member in English, German, French or Dutch), whereas all of them are classified in the IPC (Strasbourg agreement). At this moment, China alone produces each year more patent documents than all other offices in the world together. The decrease in the fraction of patents classified in CPC is therefore to be explained by the decrease in the proportion of “CPC classified collection” vs “total patents published” along the years, and emphasised in recent years due to the increase in Asian documentation.

• However, following bilateral agreements by the EPO / USPTO, a number of offices (China, Korea, Russia, Brazil ...) are now also classifying their new applications in CPC. Therefore, all major offices (except Japan) will soon be classifying in CPC, whereby the fraction classified in CPC should be growing again in the coming years.

More information about the CPC classification scheme can be found on this dedicated CPC website:
http://www.cooperativepatentclassificat ... index.html

For the above answer, I have to pay tribute to my expert classification colleagues who can be reached through the dedicated CPC website.
Best regards,

Geert Boedt
PATSTAT support
Business Use of Patent Information
EPO Vienna

Post Reply