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Working Paper
The Paper Trail of Knowledge Spillovers: Evidence from Patent Interferences [REVISED]
REVISED 9/2019: We show evidence of localized knowledge spillovers using a new database of multiple invention from U.S. patent interferences terminated between 1998 and 2014. Patent interferences resulted when two or more independent parties simultaneously submitted identical claims of invention to the U.S. Patent Office. Following the idea that inventors of identical inventions share common knowledge inputs, interferences provide a new method for measuring spillovers of tacit knowledge compared with existing (and noisy) measures such as citation links. Using matched pairs of inventors to ...
Working Paper
Spreading Out Across Expanding Idea Space
Over nearly two centuries, U.S. inventions have become increasingly dissimilar: not just fewer head-to-head collisions between inventors, but growing distance between neighboring inventions. We document this secular decline in similarity using validated neural language models applied to the full text of claims in over 11 million U.S. patents (1836–2023), corroborated by a 98 percent decline in patent interference rates, a measure of independent simultaneous invention. Measuring this correctly requires validation, since different representations of the same patent text can yield opposite ...