When does elastic labor supply cause an inverted-U effect of patents on innovation?

This study analyzes how patent protection affects innovation in an R&D-based growth model with elastic labor supply. We find that increasing patent breadth may generate an inverted-U effect on innovation depending on whether the model features the knowledge-driven or lab-equipment innovation process. This result highlights an important interaction between elastic labor supply and the innovation process through which patent protection has an inverted-U effect as documented in recent empirical studies.