The Value of Patents as Indicators of Inventive Activity

This paper summarizes a number of studies which use patent data to examine different aspects of technological change. It describes our firm level data set construction effort; reports on the relationship between RLD expenditures and the level of patenting; analyzes the relationship between patents, R&D, and tire stock market value of firms; reports on the estimation of the value of patent rights based on European patent renewal data; and describes the use of patent data to estimate the importance of R&D spillovers. It concludes that patent data represent a valuable resource for the analysis of technological change. They can be used to study longer-run interfirm differences in inventive activity and as a substitute for R&D data where they are not available in the desired detail. It is possible also to use a firm's distribution of patenting by field to infer its position in "technological space" and use it in turn to study how R&D spills over from one firm to another. Moreover, patent renewal data, which are also becoming available in the U.S., allow one to construct more relevant "quality weighted" inventive "output" measures