Competition and Innovation: An inverted-U relationship using Japanese industry data

This study replicates a model of Aghion et al. ("Competition and Innovation: An inverted-u relationship," <i>Quarterly Journal of Economics</i> 2005; 120(2):701-728), which suggests that an inverted-U relationship exists between competition and innovation. We apply patent data and a competition measure based on Japanese firm-level and industry-average data from 1964 to 2006. In a constant slope model using a full dataset, we find the same inverted-U relationship as did Aghion-Bloom-Blundell-Griffith-Howitt (ABBGH). In decade and industry fixed-effects slope models, we find the inverted-U relationship to be fragile.