Death squad or quality improvement? The impact of introducing post-grant review on U.S. patent legal quality

We investigate how the introduction of post-grant reviews at the U.S. Patent and Trademark Office through the America Invents Act (AIA) has influenced the behavior of patent applicants and examiners. This reform may incentivize applicants to narrow the scope of their patents, thereby reducing the risk of post-grant reviews and enhancing patent legal quality. To test this hypothesis, we employ a standard Difference-in-Differences (DID) analysis and find that applicants are more likely to narrow the scope of their patents. This change has resulted in fewer challenges to U.S. patents, yielding estimated annual savings of 62 to 148 million. When applicants do not preemptively narrow the scope during filing, we observe tougher scrutiny during the examination process, as examiners effectively compensate for the applicant’s lack of action. However, this “disciplinary effect” of narrowing patent scope is absent in complex fields characterized by patent thickets, where the reform does not lead to significant improvements in U.S. patent legal quality.