Cities vary with regard to the characteristics of their economic life. A formal model by Duranton and Puga (2001) suggests a division of labour between diversified and specialized cities. Diversified cities (the “nursery cities”) provide a fertile environment for search and innovation....

In this paper we measure technological relatedness between industries using a dataset on product portfolios of plants. For this purpose we first develop a general methodology to extract data on co-occurrences of classes (e.g. industries) in a single entity (e.g. a plant) to construct estimates...

In this paper, the changing roles of agglomeration externalities during different stages of the industry life cycle are investigated. A central argument is that agglomeration externalities vary with mode of competition, innovation intensity, and characteristics of learning opportunities in...