Technological evolution seen from the USPC reclassifications

Abstract

This study aimed to investigate technological evolution from the perspective of the US Patent Classification (USPC) reclassification. Similar to the revisions of the Dewey Decimal Classification, a commonly used library classification scheme, USPC reclassification takes the forms of creating, abolishing or modifying USPC class schedules. The results showed that there exist significant differences among five types of patents based on the USPC reclassification: Patents reclassified to Class 001 (classification undetermined), Patents with Technological Inter-field Mobilised Codes, Patents with Technological Intra-field Mobilised Codes, Patents with Abolished Codes, and Patents with Original Codes. Patents reclassified to Class 001, mostly related to the topic of "Data processing", performed better than other patents in novelty, linkage to science, technological complexity and innovative scope. Patents with Inter-field Mobilised Codes, related to the topics of "Data processing: measuring, calibrating, or testing" and "Optical communications", involved broader technology topics but had a low speed of innovation. Patents with Intra-field Mobilised Codes, mostly in the Computers & Communications and Drugs & Medical fields, tended to have little novelty and a small innovative scope. Patents with Abolished Codes and patents with Original Codes performed similarly--their values of patent indicators were low. It is suggested that future research extend the patent sample to subclasses or reclassified secondary USPCs in order to understand the technological evolution within a field in greater detail.