Long live patents: the increasing life expectancy of patent applications and its determinants

Relying on a comprehensive dataset including detailed information on all patent applications filed to the EPO from 1980 to 2000 and on the renewal of those of them that were granted, this paper presents the first survival time analysis of the determinants of patent length. The results are threefold: first, they clearly establish that the life expectancy of patent rights has significantly increased over the past decades despite a small decline in the average grant rate. Second, they show that some filing strategies strongly influence the length of patents, possibly due to induced delays in the examination process. And third, they confirm that more valuable patents (more cited or covering a larger geographical scope) tend to live longer.