The (Unnoticed) Revitalization of the Doctrine of Equivalents

56 Pages Posted: 11 Feb 2021 Last revised: 13 Apr 2022

See all articles by Daryl Lim

Daryl Lim

Pennsylvania State University, Dickinson Law; Fordham University - Fordham Intellectual Property Institute

Date Written: February 11, 2020


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

Suggested Citation

Lim, Daryl, The (Unnoticed) Revitalization of the Doctrine of Equivalents (February 11, 2020). St. John's Law Review , Forthcoming, Available at SSRN:

Daryl Lim (Contact Author)

Pennsylvania State University, Dickinson Law ( email )

150 S College St
Carlisle, PA 17013
United States


Fordham University - Fordham Intellectual Property Institute ( email )

150 West 62nd Street, Rm 7-145
New York, NY 10023
United States

Do you have negative results from your research you’d like to share?

Paper statistics

Abstract Views
PlumX Metrics