PATENTS AND GROWTH IN OLG ECONOMY WITH PHYSICAL CAPITAL

We study the implications of patents in an overlapping generations model with horizontal innovation of differentiated physical capital. We show that within this demographic structure of finitely lived agents, weakening patent protection generates two contradicting effects on innovation and growth. Weakening patent protection lowers the (average) price of patented machines, thereby increasing machine utilization, output, aggregate saving, and investment. However, a higher demand for machines shifts investment away from the R&D activity aimed at inventing new machine varieties toward the formation of physical capital. The growth-maximizing level of patent protection is incomplete. Shortening patent length is more effective than loosening patent breadth in spurring growth, due to an additional positive effect on growth, that is decreasing investment in old patents. Welfare can be improved by weakening patent protection beyond the growth-maximizing level.

Cross-industry growth differences with asymmetric industries and endogenous market structure

We develop a two-industry R&D growth model with a free-entry endogenous market structure to evaluate the impact of industrial fundamentals on cross-industry differences of TFP growth and R&D intensity. Endogenous market structure in our model allows the firm’s market size to respond to the firm’s entry and exit which complements the models with an exogenous market structure in the previous literature. We find that surprisingly, an industry with a relatively high R&D productivity or appropriability exhibits “relatively” low in-house innovation growth and R&D intensity during transition. Moreoever, we examine the effects of R&D subsidies and patent breadth policies on industry differences by implementing both asymmetric and symmetric policy rules. We find that only asymmetric R&D subsidies have impacts on TFP growth and R&D intensity differences.