Innovation and Imitation with and without Intellectual Property Rights

An extensive empirical literature indicates that returns from innovation are appropriated primarily via mechanisms other than formal intellectual property rights -- and that `imitation' is itself a costly activity. However most theory assumes the pure nonrivalry of `ideas' with its implication that, in the absence of intellectual property, innovation (and welfare) is zero. This paper introduces a formal model of innovation based on imperfect competition in which imitation is costly and an innovator has a first-mover advantage. Without intellectual property, a significant amount of innovation still occurs and welfare may actually be higher than with intellectual property.