Working Papers

Barriers to Integration: Physical Boundaries and the Spatial Structure of Residential Segregation

with Jackelyn Hwang
Despite modest declines in residential segregation levels since the Civil Rights Era, segregation remains a defining feature of the U.S. landscape. This study highlights the importance of considering physical barriers—features of the urban environment that disconnect locations—when measuring segregation. We use population and geographic data for 20 U.S. Rustbelt cities from the 2010 decennial census and a novel approach for measuring and analyzing segregation that incorporates the connectivity of roads and the excess distance imposed by physical barriers, such as highways, railroad tracks, and dead-end streets. We find that physical barriers divide urban space in ways that reinforce or exacerbate segregation, but there is substantial variation in the extent to which they increase segregation both within and across these cities and for different ethnoracial groups. By uncovering a new source of variation in the segregation experienced by city residents, the findings have implications for understanding the mechanisms that contribute to the persistence of segregation and the consequences of segregation.

The Divergence Index: A Decomposable Measure of Segregation and Inequality

Decomposition analysis is a critical tool for understanding the social and spatial dimensions of inequality, segregation, and diversity. In this paper, I propose a new measure -- the Divergence Index -- to address the need for a decomposable measure of segregation. Although the Information Theory Index has been used to decompose segregation within and between communities, I argue that it measures relative diversity not segregation. I demonstrate the importance of this conceptual distinction with two empirical analyses: I decompose segregation and relative homogeneity in the Detroit metropolitan area, and I analyze the relationship between the indexes in the 100 largest U.S. cities. I show that it is problematic to interpret the Information Theory Index as a measure of segregation, especially when analyzing local-level results or any decomposition of overall results. Segregation and diversity are important aspects of residential differentiation, and it is critical that we study each concept as the structure and stratification of the U.S. population becomes more complex.

The Spatial Proximity and Connectivity (SPC) Method for Measuring and Analyzing Residential Segregation

In recent years, there has been increasing attention to the spatial dimensions of residential segregation, such as the spatial arrangement of segregated neighborhoods and the geographic scale or relative size of segregated areas. However, the methods used to measure segregation do not incorporate features of the built environment, such as the road connectivity between locations or the physical barriers that divide groups. This article introduces the Spatial Proximity and Connectivity (SPC) method for measuring and analyzing segregation. The SPC method addresses the limitations of current approaches by taking into account how the physical structure of the built environment affects the proximity and connectivity of locations. In this article, I describe the method and its application for studying segregation and spatial inequality more broadly. I demonstrate one such application—analyzing the impact of physical barriers on residential segregation—with a stylized example and an empirical analysis of racial segregation in Pittsburgh, PA. The SPC method contributes to scholarship on residential segregation by capturing the effect of an important yet understudied mechanism of segregation—the connectivity, or physical barriers, between locations—on the level and spatial pattern of segregation, and enables further consideration of the role of the built environment in segregation processes.