Multilayer patent citation networks: A comprehensive analytical framework for studying explicit technological relationships

TL;DR

This paper introduces a multilayer network framework for patent citation analysis that incorporates citation context and cross-jurisdictional data, providing a more nuanced understanding of technological relationships.

Contribution

It proposes a novel multilayer approach to patent citation networks that captures citation context and cross-border links, improving the analysis of technological relationships.

Findings

Multilayer networks contain complementary information to single-layer networks.

Communities in multilayer networks better match established technological similarity networks.

Multilayer approach captures more nuanced technological relationships.

Abstract

The use of patent citation networks as research tools is becoming increasingly commonplace in the field of innovation studies. However, these networks rarely consider the contexts in which these citations are generated and are generally restricted to a single jurisdiction. Here, we propose and explore the use of a multilayer network framework that can naturally incorporate citation metadata and stretch across jurisdictions, allowing for a complete view of the global technological landscape that is accessible through patent data. Taking a conservative approach that links citation network layers through triadic patent families, we first observe that these layers contain complementary, rather than redundant, information about technological relationships. To probe the nature of this complementarity, we extract network communities from both the multilayer network and analogous single-layer networks, then directly compare their technological composition with established technological similarity networks. We find that while technologies are more splintered across communities in the multilayer case, the extracted communities match much more closely the established networks. We conclude that by capturing citation context, a multilayer representation of patent citation networks is, conceptually and empirically, better able to capture the significant nuance that exists in real technological relationships when compared to traditional, single-layer approaches. We suggest future avenues of research that take advantage of novel computational tools designed for use with multilayer networks.