A fresh look at patent citations

The number of times a patent is referenced by other patents is generally seen as a good indication of its value and its innovative contribution. However, there are three key issues with the practical application of this indicator, which is better known as patent citations, which obfuscate its use and thus threaten the validity of studies in which it is applied. This doctoral thesis will discuss and remedy these three problems.

The first issue concerns the various methods that are in use to calculate patent citations. The results presented in this thesis indicate that these methods produce substantially different indicators and that generally indicators based on patent families, i.e. groups of related patents, present themselves as the preferred option. Next, it is found that patent citations and patent value are related through a log-linear relation, as opposed to the often-used linear relation. Starting from the legal and procedural role of citations, this thesis posits that patent citations relate to economic value albeit in two, distinctive, ways. These assertions are validated and empirically confirmed in this thesis.

Overall, the results of this thesis are relevant to improve the measurement and understanding of patent citations. By doing so, this should further the understanding of innovation and intellectual property.