What are patent families?
Patent families can be defined as “a collection of published patent documents relating to the same invention, or to several inventions sharing a common aspect, that are published at different times in the same country or published in different countries or regions” (WIPO, 2012).
Numerous types of patent families have been defined, which generally differ in terms of how closely related their members must be in order to be considered to be members of the same family. Most types of patent families are understood to be related to each other through one or more common “ancestors”, patent documents on the basis of which priority has been claimed. For example, a first patent application for an invention might be filed in Mexico, with subsequent patent applications for the same invention being filed in Germany and South Africa claiming priority based on the first application (in Mexico). These three documents would be considered members of the same patent family.
Why should I care about patent families?
Grouping patent documents according to families can help you:
- Get an overview of different patent documents relating to a specific invention published within a given country or across different countries. This overview can indicate the different countries and regions in which a patent applicant aims to (and may ultimately succeed in) obtaining patent protection for a specific invention. For example, you might be aware that a patent application had been filed in the Russian Federation for an invention you want to exploit, and by identifying its patent family members you could determine where else this invention might be protected. Having different patent documents relating to the same invention grouped together can also make it easier to find a document related to this invention in a language you understand, keeping in mind that these documents might not be completely identical (in particular in their claims). For example, if you found a patent document in Chinese, you might be able to find a patent family member in English that could give you an idea of what the Chinese document was all about.
- Avoid treating multiple patent documents relating to the same invention as separate in your search results and analysis of these results. For example, if you wanted to determine the number of inventions for which patent protection had been sought in a specific field of technology, you would not want to count the number of patent applications filed (many of which might represent the same inventions) but rather the number of patent families (each representing a different invention).
How do patent database systems relate to patent families?
Patent database systems can make it easier to find different patent documents belonging to a patent family by harmonizing document identification numbers (in particular priority numbers) or directly providing links from patent documents to the other documents in the patent family. For example, WIPO's PATENTSCOPE provides references from international patent applications filed under the Patent Cooperation Treaty (PCT) to national patent applications made based on these international applications. These references can be found in the “National Phase” tab in the detailed view for international patent applications. Similarly, PATENTSCOPE makes it possible to access the international patent application on the basis of which a national patent application was made from the detailed view for these “national phase entries”.
Patent database systems can also group search results according to patent families. A single patent document is shown in search results as the “representative member” of the patent family. For example, EPO's Espacenet selects as the representative member for each patent family (in order of priority) a European patent document in English, US patent document, or British patent document, where available. Grouping search results in this manner avoids having the same invention appear multiple times in search results. Currently, PATENTSCOPE does not group search results according to patent families. Consequently, results analyses rank results according to the number of documents retrieved rather than the number of patent families.
Where can I find more information about patent families?
More information about patent families and their different specific definitions can be found in the WIPO Handbook on Industrial Property Information and Documentation [PDF, 304kB] (Appendix III). Intellogist also provides a useful discussion of patent families.
References
WIPO, 2012. Handbook on Industrial Property Information and Documentation.
Anthony Trippe has posted interesting articles entitled "Why I Don't Use Extended Patent Families When Counting Patents" and "Counting Documents When Conducting a Patent Analysis Project" on his Patinformatics blog. The articles discuss the relationship between patent families and inventions encompassed by these patent families, contrasting the "one document per family" approach with the "one document per invention" approach.
Useful reading for anyone interested in doing statistical analysis based on patent families!