Patent Classification Systems and Technological Categorization: An Overview and Update

Abstract

Patent classification systems and upper-level grouping datasets have been widely used for research and entrepreneurial purposes but are insufficiently documented. This article provides an overview of the major patent classification systems and the basic ideas behind categorization of the data on patent classes. I highlight recent institutional changes that disproportionately affect patents in specific categories and alternative categorizations used in the patent examination process. Finally, I update the National Bureau of Economic Research patent technological categorization based on the latest U.S. patent classification. The resulting datasets can be used in numerous follow-up analyses using patent data to investigate innovation and entrepreneurship.