This paper considers those sectors of the economy that operate under the same regimes of rewarding private innovators as others, but differ in that they face recurring problems of resistance, as occur in the pharmaceutical and agricultural industries. This recurrence originates in the natural...

Using a general two-stage framework, this paper gives sufficient conditions for increasing competition to have negative or positive effects on R&D-investment, respectively. Both possibilities arise in plausible situations, even if one uses relatively narrow definitions of increasing competition....