Is the Dissimilarity Index with Multi-modal Accessibility a Useful Tool for Measuring Spatial Mismatch

The dissimilarity index is a useful tool for understanding the spatial mismatch, or geographic separation, between groups. Specifically the measure is often used to show patterns of residential segregation between racial and ethnic groups in a geographic area. Steven Raphael and Michael Stoll in “Modest Progress: The Narrowing Spatial Mismatch Between Blacks and Jobs in the 1990s” use the index of dissimilarity to show the disproportionate separation of blacks from employment opportunities. The authors contend that blacks remain the most residentially segregated from employment opportunities than any other racial or ethnic group, despite declines in dissimilarity over the last decade. The goal of this paper is to utilize the dissimilarity index to determine its relevance as a measure of accessibility by providing an analysis of the segregation between blacks and whites and employment opportunities in the Twin Cities metropolitan area. Specifically, the 1990 Census Transportation Planning Package is used to gather information on population, employment opportunities, and median auto and transit commute times in Traffic Analysis Zones in the central city and developed suburbs. The background section of the paper provides information on the dissimilarity index and its relation to the jobs/housing balance and spatial mismatch; the use of the dissimilarity index as a measure of accessibility and spatial mismatch; and the effects a jobs/housing imbalance might have on behavior. The paper goes on to 1) review a sampling of the extensive literature on spatial mismatch, 2) explain the methodology employed in this study, 3) present an interpretation of the results, and 4) ends with concluding remarks. Background