Incidence and Growth of Patent Thickets - the Impact of Technological Opportunities and Complexity
Georg Von Graevenitz
University of East Anglia in London; Center for Competition Policy
ESMT European School of Management and Technology
University of Munich - Munich School of Management; Centre for Economic Policy Research (CEPR); Center for European Economic Research (ZEW); Institute for Fiscal Studies (IFS); CESifo (Center for Economic Studies and Ifo Institute for Economic Research)
CEPR Discussion Paper No. DP6900
We investigate incidence and evolution of patent thickets. Our empirical analysis is based on a theoretical model of patenting in complex and discrete technologies. The model captures how competition for patent portfolios and complementarity of patents affect patenting
incentives. We show that lower technological opportunities increase patenting incentives in complex technologies while they decrease incentives in discrete technologies. Also, more competitors increase patenting incentives in complex technologies and reduce them in discrete technologies. To test these predictions a new measure of the density of patent thickets is introduced. European patent citations are used to construct measures of fragmentation and technological opportunity. Our empirical analysis is based on a panel capturing patenting behavior of 2074 firms in 30 technology areas over 15 years. GMM estimation results confirm the predictions of our theoretical model. The results show that patent thickets exist in 9 out of 30 technology areas. We find that decreased technological opportunities are a surprisingly strong driver of patent thicket growth.
Number of Pages in PDF File: 45
Keywords: complexity, patent portfolios, patent thickets, patenting, technological opportunities
JEL Classification: L13, L20, O34working papers series
Date posted: August 20, 2008
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