This paper provides a direct measure of the density of patent thickets based on patent citations. We discuss the algorithm that generates the measure and present descriptive results validating it. Moreover, we identify technology areas particularly affected by patent thickets.

Escalation of advertising or R&D expenditure can give rise to endogenous barriers to entry. This paper investigates whether escalation of investments in R&D raises the return to investments in advertising or vice versa. We provide three empirical tests using a dataset which combines stock market...

This paper exploits enlargement of the European Union as a natural experiment to provide evidence for cluttering of the trade mark register in Europe. Enlargement increased regulatory uncertainty for pharmaceutical firms because the number of medical regulators that had to approve invented names...

The existing literature identifies patent thickets indirectly. In this paper we propose a novel measure based on patent citations which allows us to measure the density of patent thickets directly. We discuss the algorithm which generates the measure and present descriptive results validating...

This paper considers the integration of competition policy and innovation policy in the context of R&D cooperation. An explicit comparison of the welfare losses under ex-ante and ex-post R&D cooperation reveals differing incentives to undertake R&D in both regimes. The strength of these...

We analyse economic welfare in R&D intensive industries under varying assumptions on the spillover process. The focus lies on spillover processes with complementary R&D investments such as those modelling absorptive capacity. There spillovers give rise to both negative and positive...