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.

This paper introduces a model of coordination of research paths into the theory of Research Joint Ventures (RJVs). A comparison of RJVs and licensing by non-cooperative firms shows that the latter may be unable to co-ordinate on complementary research paths whereas RJVs are always able to do...

Post-grant validity challenges at patent offices rely on the private initiative of third parties to correct mistakes made by patent offices. We hypothesize that incentives to bring post-grant validity challenges are reduced when many firms benefit from revocation of a patent and when firms are...

Licensing in a patent thicket allows firms to either avoid or resolve hold-up. Firms’ R&D incentives depend on whether they license ex ante or ex post. We develop a model of a patent portfolio race, which allows for endogenous R&D efforts, to study firms’ choice between ex ante and ex post...

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...

At least two: the reputation of their brand and a reputation for being tough on imitators of this brand. Sustaining a brand requires both investment in its reputation amongst consumers and the defence of the brand against followers that infringe upon it. I study the defence of trade marks...

I develop a model of R&D cooperation with uncertain research outcomes. In this model asymmetric outcomes of R&D competition emerge naturally. Therefore ex-ante and ex-post R&D cooperation can be studied as alternatives for firms. Using this model I compare welfare losses under ex-ante and...

Entrepreneurship education ranks highly on policy agendas in Europe and the US, butlittle research is available to assess its impacts. In this context it is of primary importanceto understand whether entrepreneurship education raises intentions to be entrepreneurialgenerally or whether it helps...