The Technology Relevance measures the importance of a patent family (invention) for technological development. It is calculated based on the number of worldwide prior art citations received from other patent families. In numerous scientific studies this metric has been found to be a valid indicator of the importance of the invention.
Citation-based indicators are also used with great success in other domains: The Google search engine uses citations between web pages to estimate the importance of these pages. Scientists evaluate the impact of their research based on the number of citations they receive.
For the Technology Relevance, prior art citations made by patent examiners from around the world are considered to compile a true view of the overall worldwide impact of an invention on technical development. We consider prior art citations from many patent offices such as, e.g., USPTO, EPO, WIPO, German Patent Office, Japanese Patent Office and many others. PatentSight also considers citations made by the applicants (applicant citations), which account for roughly 15% of all citations in the database.
The number of patent citations is adjusted by the following three factors:
- Patent Office Citation Practices
Citation practices can differ by patent office. The USPTO, for example, cites on average significantly more than other patent offices. To take such differences into account, a citation from a patent office that, on average, makes less citations is weighted higher than a citation from a patent office that, on average, makes more citations.
Moreover, if a patent family is cited by more than one member of another patent family, the citation that is weighted the highest is used for the calculation of the Technology Relevance.
For more details, see also: → What is Family-to-Family Citation?
- Age of the Patent Family
On average, older patent families tend to receive more citations than patent families that have only recently been published.
To correct for the age of a patent family, the number of citations received by the patent family is divided by the average number of citations received by all patent families that have been published in the same year .
- Citation Differences Between Technology Fields
The average number of citations can also significantly differ depending on the technology field. For example, patent families from the field of mining technologies might, on average, receive fewer citations than patents from the field of heterocyclic compounds.
The number of citations a patent family has received (which, at this stage, has already been corrected for the patent office citation practice and the age of the patent family) is therefore divided by the average number of citations received by all patent families in same the technology field(s). In this, the 4-digit IPC level 3 is used to assign patent families to technology fields.
Consequently, the Technology Relevance can be defined as a relative measure that compares a patent family to other patent families. For example, a value of "2" means that a patent family is twice as relevant for technological developments as an average patent family in the same technology field and of the same age.