In the last years, there has been substantial pushback against the patent system. Critics claim that patent rights are becoming an impediment to innovation, and an instrument to extract rents through patent litigation. This column develops a framework to quantitatively assess the effectiveness of the current US patent system and the welfare impact of reforms. It finds that the current system generates positive social value, and that the recent introduction of the Patent Trial and Appeal Board increased welfare. Intensifying patent office examination and imposing antitrust limits on patent licensing agreements would yield additional welfare gains.