Used, blocking and sleeping patents: Empirical evidence from a large-scale inventor survey

This paper employs data from a large-scale survey (InnoS&T) of inventors in Europe, the USA, and Japan who were listed in patent applications filed at the European Patent Office with priority years between 2003 and 2005. We provide evidence regarding the reasons for patenting and the ways in which patents are being utilized. A substantial share of patents is neither used internally nor for market transactions, which confirms the importance of strategic patenting and inefficiency in the management of intellectual property. We investigate different types of unused patents - unused blocking patents and sleeping patents. We also examine the association between used and unused patents and their characteristics such as family size, scope, generality and overlapping claims, technology area, type of applicant, and the competitive environment from where these patents originate. We discuss our results and derive some implications for innovation and patent policy.