The diffusion of homicide across neighbourhoods: A social ecological case study of Buffalo, New York, 1950--1999

Recent scholarly attention has been directed at examining how violence spreads across the urban landscape through a process of diffusion. Couched within an in-depth, historical, case-study approach, this dissertation shows that homicide exhibits a process of 'relocation diffusion' across neighbourhoods in Buffalo between 1950 and the end of the twentieth century. The findings illustrate that this gradual diffusion process is observable only when the scope of the research extends over three or more decades. Spatial analytic and traditional multivariate methodologies provide evidence that both supports and refutes a racial invariance hypothesis. This hypothesis stipulates that differences in neighbourhood crime rates are attributable to differences in social structural characteristics and, moreover, that these effects are not race-specific. In support of this hypothesis, this study shows that neighbourhood homicide rates in Buffalo are driven by poverty and related disadvantages, rather than racial composition; however, this is true only during the later decades of the twentieth century. By contrast, in employing a novel methodology that combines Exploratory Spatial Data Analysis and multinomial logit regression, the results show that racial composition is important in increasing a neighbourhood's vulnerability to the diffusion of homicide from adjoining areas. In effect, African American neighbourhoods in Buffalo are in a precarious position as a function of their spatial proximity to a smaller cluster of highly violent neighbourhoods. Additional analyses are aimed at investigating the degree of historical contingency in the types of characteristics that cluster in neighbourhoods, and the effects of these characteristics on both within-neighbourhood homicide rates and the diffusion of homicide over time. These issues are examined through the lens of the distinctive urban context and social history of Buffalo---a mid-sized, north-eastern, industrial centre that has undergone dramatic social, economic, and demographic transitions during the post-industrial era. To investigate the central questions driving this research, tract-level census data are linked to data on homicide incidents in Buffalo between 1950 and 1999. This dissertation extends the extant literature by providing a nuanced quantitative account of the relationship between neighbourhoods and homicide, embedded within an historical case-study approach that integrates the social ecology of violence in Buffalo.