The Rise of Process Claims : Evidence from a Century of U.S. Patents

We document the occurrence of process claims in granted U.S.\ patents over the last century. Using novel data on the type of independent patent claims, we show an increase in the annual share of process claims of about 25 percentage points (from below 10% in 1920). This rise in process intensity is not limited to a few patent classes but can be observed across a broad spectrum of technologies. Process intensity varies by applicant type: companies file more process-intense patents than individuals, and U.S. applicants file more process-intense patents than foreign applicants. We further show that patents with higher process intensity are more valuable but are not necessarily cited more often. Last, process claims are on average shorter than product claims; but this gap has narrowed since the 1970s. These patterns suggest that the patent breadth and scope of process-intense patents are overestimated when claim types are not accounted for. We conclude by describing in detail the code used to construct the claim-type data, showing results from a data-validation exercise (using close to 10,000 manually classified patent claims), and providing guidance for researchers on how to alter the classification outcome to adapt to researchers' needs