Guest Talk "The Coherence of US Cities"


The next talk on the invited research talks series will be given by Simone Daniotti [1], a PhD candidate from Complexity Science Hub (CSH) Vienna. 


Title: The Coherence of US Cities

Date/Time: 03.07.2024, 12:00-13:00

Location: D2.2.094


Diversity is a critical factor in economic development, providing resilience against sector-specific shocks, fostering innovation, and enabling the expansion of economic activities. However, how much diversity cities can effectively handle remains an open question. This paper introduces a novel metric, "coherence," to assess the technological or cognitive distance between workers in the economic activities present in the city. Examining US cities from 1850 to 2022, we find that, despite rapid changes in specialization patterns, the average coherence of cities' specializations across the urban system remains remarkably stable. Notably, the relationship between coherence and city size is consistently negative, implying that larger cities exhibit lower coherence. This finding suggests that as cities grow, they can support new activities, with a predictable decrease in coherence. Our results indicate the existence of a systematic mapping between the capabilites of a city and its size. This stability in coherence challenges expectations of significant diversification over time and prompts further investigation into the mechanisms that govern the interplay between city size, relatedness, and diversification. The paper contributes to the ongoing discourse on regional development, offering insights into the limits of diversity within urban systems and the implications for the evolution of cities over time.



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