Long-run dynamics of the U.S. patent classification system
Date: 04 January 2019Almost by definition, radical innovations create a need to revise existing classification systems. In this paper, we argue that classification system changes and patent reclassification are common and reveal interesting information about technological evolution. To support our argument, we present three sets of findings regarding classification volatility in the U.S. patent classification system. First, we study the evolution of the number of distinct classes. Reconstructed time series based on the current classification scheme are very different from historical data. This suggests that using the current classification to analyze the past produces a distorted view of the evolution of the system. Second, we study the ...
Long-run dynamics of the US patent classification system
Lafond, F. & Kim, D. (2019). 'Long-run dynamics of the US patent classification system'. Journal of Evolutionary Economics: https://doi.org/10.1007/s00191-018-0603-3