Data Description and Collection
Description of the Data Source
We collected data from the OECD Citations Database. This section provides the main information about this database, its primary sources and how the data is combined and structured in the database. The second part of the section is dedicated to the description of the International Patent Classification (IPC) codes and their role for research.
The OECD Citations Database is an international database that provides information on international patent citations that allow us capturing knowledge and invention flows. It is built upon the data provided by the European Patent Office and taken from EPO’s Worldwide Statistical Patent Database PATSTAT as of October 2012. If required, all patent documents included in the OECD Citations Database can be connected to this primary data source. PATSTAT contains patent and non-patent literature citations referenced in patent applications that were filed between 1977 and October 2012 directly to the European Patent Office or via the Patent Cooperation Treaty at national offices, or other international offices such as WIPO, UPSTO, JPO etc. According to the database statistics, about 98 % of the patents contain citations. Due to the described reasons, it is important that the citations are made by examiners as a result of European and international patentability searches. Most of the OECD citations are examiner citations. For all EPO patents there are aggregate counts of both backward and forward citations. The database also shows the origin of each citation which makes it feasible to study the geography of the citations. We also require the data on patent applicants and inventors. It is not included in the OECD Citations Database and therefore achieved from the OECD REGPAT database as of January 2013.
The International Patent Classification (IPC) scheme forms the structure of the database. IPC is an international system, which is applied by 52 countries and four international organizations. The structure of IPC is organized by sections, classes, subclasses, groups and subgroups by which technologies are classified. In the OECD Citations Database, IPC classes also play the role of a retrieval system for the patent documents describing certain technologies. It makes it possible to request the inventions in the concrete technological field.