英文标题:
《Long-run dynamics of the U.S. patent classification system》
---
作者:
Francois Lafond and Daniel Kim
---
最新提交年份:
2018
---
英文摘要:
Almost 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 relative sizes of classes. The size distribution is exponential so classes are of quite different sizes, but the largest classes are not necessarily the oldest. To explain this pattern with a simple stochastic growth model, we introduce the assumption that classes have a regular chance to be split. Third, we study reclassification. The share of patents that are in a different class now than they were at birth can be quite high. Reclassification mostly occurs across classes belonging to the same 1-digit NBER category, but not always. We also document that reclassified patents tend to be more cited than non-reclassified ones, even after controlling for grant year and class of origin.
---
中文摘要:
几乎从定义上讲,激进的创新需要修改现有的分类系统。在本文中,我们认为分类系统的变化和专利重新分类是常见的,并揭示了有关技术演变的有趣信息。为了支持我们的论点,我们提出了三组关于美国专利分类体系中分类波动性的研究结果。首先,我们研究了不同类数的演化。基于当前分类方案重建的时间序列与历史数据有很大不同。这表明,使用当前的分类来分析过去会对系统的演化产生扭曲的看法。其次,我们研究了班级的相对规模。大小分布呈指数分布,因此类的大小差别很大,但最大的类不一定是最古老的类。为了用一个简单的随机增长模型来解释这种模式,我们引入了一个假设,即类有一个规则的分裂机会。第三,我们研究重新分类。与出生时不同类别的专利所占份额可能相当高。重新分类主要发生在属于同一个1位数NBER类别的类别之间,但并不总是如此。我们还记录了重新分类的专利往往比未重新分类的专利更容易被引用,即使在控制了授予年份和来源类别之后。
---
分类信息:
一级分类:Quantitative Finance 数量金融学
二级分类:Economics 经济学
分类描述:q-fin.EC is an alias for econ.GN. Economics, including micro and macro economics, international economics, theory of the firm, labor economics, and other economic topics outside finance
q-fin.ec是econ.gn的别名。经济学,包括微观和宏观经济学、国际经济学、企业理论、劳动经济学和其他金融以外的经济专题
--
---
PDF下载:
-->