This paper shows that dynamic inefficiency can occur in dynamic general equilibrium models with fully optimizing, infinitely-lived households even in a situation with underinvestment. We identify necessary conditions for such a possibility and illustrate it in a standard R&D-based growth model....

Empirical evidence suggests that positive externalities from R&D exceed negative ones. According to conventional wisdom, this calls for R&D subsidies. This paper develops a quality-ladder growth model with overlapping generations which evaluates the positive and normative implications of R&D...