Cumulative innovation is central to economic growth. Do patent rights facilitate or impede such follow-on innovation? This paper studies the causal effect of removing patent protection through court invalidation on subsequent research related to the focal patent, as measured by later citations....

We study the determinants of patent suits and their outcomes over the period 1978-1999 by linking detailed information from the U.S. patent office, the federal court system, and industry sources. The probability of being involved in a suit is very heterogeneous, being much higher for valuable...