The (Unnoticed) Revitalization of the Doctrine of Equivalents

Abstract

Earlier empirical studies unanimously concluded that patent law’s doctrine of equivalents was dead. This Article presents data revealing the doctrine’s unnoticed revitalization and its more recent evolution. Patentees are winning at significantly higher rates than they were a decade ago. The doctrine has transitioned from cases involving primarily mechanical inventions to those in the “new economy” – drugs and medical devices, as well as computer and communications-related inventions. The Article also reports on other findings of interest to academics and practitioners, including how judges applied the doctrine, its limitations and exceptions to those limitations, the role of rivalry in patentee win rates, the strategy alleged infringers use to as well as the district courts and the Federal Circuit judges shaping the doctrine today.

Keywords: patent, doctrine of equivalents, empirical