IV.5 Examining the Evolution and Distribution of Patent Classifications

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Elisha F. H. Allgood

Daniel O. Kutz

Katy Börner

Daniel O. Kutz’s research interests lie in social informatics, interaction design, and information visualization. In collaboration with information scientist Katy Börner and graphic designer Elisha F. Hardy, he developed the featured map to understand and communicate visually the intellectual coverage and evolution of the patent space of different patent holders. Patents granted between January 1, 1976, and December 31, 2002, were obtained from the United States Patent and Trademark Office (USPTO) patent archive. A simple graph shows the 140% increase in the number of patents granted over the last 25 years. The 2.5 million patents are further grouped by their classification, and changes in the number of patents per class were examined in five-year intervals. Classes that experienced slow or rapid growth are depicted and contrasted using treemaps, a space-filling technique developed at the Human-Computer Interaction Lab at the University of Maryland. To compare the evolving patent holdings of Apple Computers and a private patent holder, treemaps were placed in a time sequence. Longitudinal comparison at the classification level becomes possible, revealing an assignee’s past and current intellectual borders, patenting behavior, and maybe even a general understanding of research and development trends.


Kutz, Daniel. 2004. “Examining the Evolution and Distribution of Patent Classifications.” In Proceedings of the 8th International Conference on Information Visualisation, 983-988. Los Alamitos, CA: IEEE Computer Society.

Kutz, Daniel O., Katy Börner, and Elisha F. Hardy. 2004. Examining the Evolution and Distribution of Patent Classifications. Courtesy of Indiana University. In “4th Iteration (2008): Science Maps for Economic Decision-Makers,” Places & Spaces: Mapping Science, edited by Katy Börner and Elisha F. Hardy. http://scimaps.org.

Acknowledgements: This exhibit is supported by the National Science Foundation under Grant No. IIS-0238261, CHE-0524661, IIS-0534909 and IIS-0715303, the James S. McDonnell Foundation; Thomson Reuters; the Cyberinfrastructure for Network Science Center, University Information Technology Services, and the School of Library and Information Science, all three at Indiana University. Some of the data used to generate the science maps is from the Web of Science by Thomson Reuters and Scopus by Elsevier. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.