The Action Is Everywhere, But Greater at More Localized Spatial Scales: Comparing Concentrations of Crime across Addresses, Streets, and Neighborhoods

Recent work has debated which geographic scale is most relevant to understanding the clustering of crime and disorder across a city. This study introduces nested Gini coefficients that help answer this question by disentangling concentrations of crime at multiple scales in a single city while also controlling for artifacts of arithmetic and urban form. The study examines six indices of crime and disorder drawn from requests for government services received by the City of Boston in 2011 for addresses (N = 98,355) nested in street segments (N = 13,048) nested in census tracts (N = 178). Nested Gini coefficients assessed the average concentration at each level independent of the higher geographic unit (e.g., the streets of a single tract). Concentrations were greatest at addresses, then at streets, and then at tracts. Compared to whole-city calculations, they showed equal or greater levels of concentration of crime and disorder for addresses, but lower concentrations for streets. Controlling for the number of locations on a street or in a tract also markedly diminished concentrations. The findings indicate a continued need to explain concentrations of crime, especially at localized geographic scales