Introducing the EGO Patent Family

Patent families are a very powerful concept; they allow us to relate patents across different countries, and within countries, and are often associated with patent value (Harhoff et al, 2003). Yet, patent families can be defined in various ways, and the most appropriate definition depends on the intended application (Martinez, 2011). Often-used definitions such as patent equivalents or extended patent families are widely used and have some favourable features, yet also have some significant disadvantages. This paper argues that a different patent family, which we coin the ‘ego-patent family’, is the best alternative when one needs to understand the actual technical and legal scope of a patent family. Ego patent families are especially relevant when one wants to have insights into the legal scope of a patent (or set of patents) in the context of (cross)licensing, litigation, freedom to operate, and so on.

Ego patent families start from the perspective of a focal (ego) patent, so that there are as many families as there exist patent documents, and they are not mutually exclusive. We define the ego family of a document as “all the documents having at least one priority in common with any equivalent the given focal document”. As such, they include all patents that share legal scope with the focal patent. In contrast, fully equivalent families will often miss some patents that share legal scope with the focal patent, and extended families often include patents that share no legal scope with the focal patent. Therefore, ego patents fill a void and deserve a place in the family of patent families.

Our paper provides novel reflections on understanding patent families and their characteristics. Adding ego families to the current framework, we use a set of 36,414 patent documents disclosed as standard essential (SEPs) at ETSI to demonstrate that different patent family definitions result in considerable differences in subsequent calculations of family size, time span, ’alive’ families, geographical scope, and grant rate.