Revisiting Jane Jacobs: Quantifying urban diversity

This study attempts to formally quantify Jane Jacob's notion of urban diversity and examine whether greater diversity actually contributes economic benefits to a neighborhood. Focusing on the number and types of stores at the street level, we use the Shannon-Weaver index to quantify commercial diversity. We then compare the obtained degrees of diversity with store sales volumes obtained through credit card transaction data aggregated in the neighborhood divided into a 200-m grid. The results of the analysis, performed on 50 Spanish cities, show that the greater the diversity in the grid, the higher the sales volumes of the stores, and this tendency is more evident in large than in small-medium cities. In addition, we found that the coexistence of different store types provides a positive environment for the emergence of hub stores. We specifically define a hub store in this paper as the store with the largest revenue within a grid, provided that the distribution of the sales revenue in a grid is statistically similar to the power law. We speculate that hub stores trigger exploration between different store types, and consequently, the sales volumes of highly diverse neighborhoods increase compared with those of less diverse neighborhoods. These results highlight the importance of urban diversity for economic prosperity, which can lead to an increased quality of life for city neighborhoods.