Trends in Triadic Patent Families
Patent families are commonly constructed on the basis of information from a single patent office. While patents filed at a given patent office represent a rich source of data, these data show certain weaknesses. The “home” advantage bias is one of them, since, proportionate to their inventive activity, domestic applicants tend to file more patents in their home country than non-resident applicants. Furthermore, indicators based on a single patent office are influenced by factors other than technology, such as patenting procedures, trade flows, proximity, etc. In addition, the value distribution of patents within a single patent office is skewed: many patents are of low value and few are of extremely high value. Simple patent counts would therefore give an equal weight to all patent applications.
The OECD has developed triadic patent families in order to reduce the major weaknesses of the traditional patent indicators described above. Triadic patent families are defined at the OECD as a set of patents taken at the European Patent
Office (EPO), the Japan Patent Office (JPO) and US Patent and Trademark Office
(USPTO)* that protect a same invention. In terms of statistical analysis, they improve the international comparability of patent-based indicators, as only patents applied for in the same set of countries are included in the family: home advantage and influence of geographical location are therefore eliminated. Second, patents included in the family are typically of higher value: patentees only take on the additional costs and delays of extending protection to other countries if they deem it worthwhile.
The criteria for counting triadic patent families are the earliest priority date (first
application of the patent worldwide), the inventor’s country of residence, and fractional counts. Owing to time lag between the priority date and the availability of information, 1998 is the latest year for which triadic patent families data is almost completely available. Data from 1998 onwards are OECD estimates based on more recent patent series (“nowcasting” – see Annex A).
* USPTO patents refer to the granted patents: prior to the change in rules regarding the publication of patent applications at the USPTO, only patent grants were published. For further reading Dernis, H. and M. Khan (2004), "Triadic Patent Families Methodology", STI Working Paper 2004/2, OECD, Paris.