Patent Classifications as Indicators of Intellectual Organization

TL;DR

This study analyzes patent co-classification patterns to understand technological relationships, finding weak correlations at the classification level and suggesting alternative methods like title word mapping for better visualization of intellectual organization.

Contribution

It evaluates the effectiveness of patent classifications for mapping technological relations and proposes exploring title words as a more informative approach.

Findings

Co-classification patterns are weak indicators of technological relationships.

Country-level analysis shows limited differentiation in patent portfolios.

Title word mapping may better visualize intellectual organization.

Abstract

Using the 138,751 patents filed in 2006 under the Patent Cooperation Treaty, co-classification analysis is pursued on the basis of three- and four-digit codes in the International Patent Classification (IPC, 8th edition). The co-classifications among the patents enable us to analyze and visualize the relations among technologies at different levels of aggregation. The hypothesis that classifications might be considered as the organizers of patents into classes, and that therefore co-classification patterns--more than co-citation patterns--might be useful for mapping, is not corroborated. The classifications hang weakly together, even at the four-digit level at the country level, more specificity can be made visible. However, countries are not the appropriate units of analysis because patent portfolios are largely similar in many advanced countries in terms of the classes attributed. Instead of classes, one may wish to explore the mapping of title words as a better approach to visualize the intellectual organization of patents.