Economic Consequences of a Changing Litigation Environment: The Case of Patents

A model of patent infringement is developed to analyze the relationship between litigation and aspects of the legal environment such as the probability that the patent is found valid, the size of legal fees and their allocation across agents. Potential challengers first decide whether to infringe and then the patentee decides whether or not to prosecute. The outcome of this game has a fundamental impact on the value of patent protection to a patentee. This model is then linked to a patent renewal model which explicitly incorporates the legal parameters of interest from the litigation game. Estimates of the renewal model allow the empirical estimation of the private value of a patent protection. Simulations are presented for Germany which show the quantitative impact of changes in the legal environment on the value generated by the patent system and hence the incentives created for innovation.