As patent data become more available in machine-readable form, an increasing number of researchers have begun to use measures based on patents and their citations as indicators of technological output and information flow. This paper explores the economic meaning of these citation-based patent...

A survey of recent patentees was conducted to elicit their perceptions regarding the importance of their inventions, the extent of their communication with other inventors, and the relationship of both importance and communication to observed patent citations. A cohort of 1993 patentees were...

This paper explores the patterns of citations among patents taken out by inventors in the U.S., the U.K., France, Germany and Japan. We find (1) patents assigned to the same firm are more likely to cite each other, and come sooner than other citations; (2) patents in the same patent class are...

The extent to which new technological knowledge flows across institutional and national boundaries is a question of great importance for public policy and the modeling of economic growth. This paper develops a model of the process generating subsequent citations to patents as a lens for viewing...

We compare the geographic location of patent citations to those of the cited patents, as evidence of the extent to which knowledge spillovers are geographically localized. We find that citations to U.S. patents are more likely to come from the U.S., and more likely to come from the same state...

This paper asks the question: Can we see evidence of General Purpose Technologies in patent data? Using data on three million US patents granted between 1967 and 1999, and their citations received between 1975 and 2002, we construct a number of measures of GPTs, including generality, number of...