Technological Change and the Evolution of Patent Rights

Authors

Paul Rogerson, Chicago-Kent College of Law

Abstract

The history of patent law is characterized by a striking pattern: dramatic, recurring cycles between eras of stronger and weaker patent rights. One theory is that patent law has been adapting to waves of technological change. In periods of rapid technological progress, following major breakthroughs (like the steam engine or the microprocessor), freely granting patents tends to create thickets of overlapping claims that block innovation, and courts have reacted by weakening rights (raising the standard to obtain and enforce a patent).

Existing histories, relying on qualitative methods, have argued that this theory explains certain nineteenth-century legal developments, but have questioned whether it can explain the post-nineteenth-century period. This Article introduces new, complementary evidence that is based on a quantitative approach and covers substantially the entire two-century doctrinal history.

In particular, the Article presents a model for the correlation predicted by the technological theory (changes in the law lag behind changes in the pace of technological progress) using a dynamic ordered probit. To measure the rate of technological progress, it uses two quantitative measures from economic history: (1) the rate of productivity growth, and (2) the number of technologically significant patents issued by the United States Patent and Trademark Office. To measure changes in the law over time, it focuses on changes to an especially central doctrine—the standard of invention—and uses the judgments of doctrinal commentaries to code the law in each year.

The results both replicate the prior qualitative analyses of the nineteenth century and show that the same story extends to future periods. For nearly two centuries, courts have consistently weakened patent rights after the rate of technological progress rose, and vice versa, at a lag of roughly a decade. A one-percent rise in the rate of productivity growth, or one more technologically significant patent in force per five thousand people, has been associated with at least one step upward in the stringency of the standard of invention.

Recommended Citation

Paul Rogerson, Technological Change and the Evolution of Patent Rights, 28 Chap. L. Rev. 341 (2025).
Available at: https://digitalcommons.chapman.edu/chapman-law-review/vol28/iss2/3