1 Product market competition, R&D, and welfare

We compare the subgame perfect equilibrium emerging in four regimes of research and development (R&D) competition between duopolists: (i) full competition, (ii) coordination of research strategies, (iii) joint venture with cross licensing of patents, and (iv) full collusion in R&D and the product market. The outcome of the firms ' interaction depends on the interplay of the degree of product market competition, the similarity of the research strategies, and the cost of R&D, relatively to market size. Our main result is that each of the four regimes can, for plausible parameter combinations, yield the highest level of welfare. Therefore it is problematic to draw general rules applicable to all proposed research joint ventures