Patent Classification is a system of codes designed to organize and index the technical content of patents.
International Patent Classification: IPC used by WIPO is a hierarchical structure that divides technology into eight sections with approximately 70,000 subclass.
Cooperative Patent Classification: The Cooperative Patent Classification (CPC) system, in force from 1 January 2013, is a bilateral system which has been jointly developed by the EPO and the USPTO. It combines the best classification practices of the two offices.
EPO video on the Cooperative Patent Classification.
A patent's rights are enforceable only in the states/countries where the patent has been granted and renewal fees have been paid. To check if and where a patent is in force, abandoned, expired, or had a change in ownership, look up country codes and the legal status code. Remember that databases do have data gaps.
WIPO Country Codes (scroll down to page 4)
More about Legal Status Code and espacenet by Michael J. White, Librarian for Research Services, Queen's University.
The Patent Technology Monitoring Team (PTMT) periodically issues general statistics and miscellaneous reports that profile patenting activity at the U.S. Patent and Trademark Office (USPTO). Several PTMT reports are free while some other products and services are available at reasonable cost. Click here.
WIPO Intellectual Property Statistics : provides statistical data from IP offices world wide, along with statistical reports on world wide IP activity.
European Patent Office (EPO) statistics: statistics and annual reports on patent applications and granted patents at the EPO.
Commercial patent databases:
Free online patent databases:
For more details see Patent Database Review by Michael White, librarian from Queen's University in Kingston, Ontario.
Patent information is available to the public via many databases. It is advisable/recommended to conduct overlapping patent searches from several databases, because the coverage of the patent documents and the user interfaces differ depending on the database used.
Most patents are written in such a way as to make finding them difficult. Because of this, commercial databases can bring more value by offering rewritten titles and abstracts and making them easier to find.
How to search for Patents courtesy of University of Central Florida libraries (good video!)
Intellectual Property Essentials for Academic Researchers (available from the Regents of the University of California under a Creative Commons' Attribution-Non-commercial-ShareAlike 3.0 unported license
USPTO.gov patent search information and tutorials
WIPO tutorials on Patent Basics; Patent Search and Retrieval; and Patent Analysis
How to read a patent by Patent Lens
The Lens has tools for evaluating and annotating patents.