Neighbourhood, Dwelling and Apartment Building Income Mixing: Measures and Experimental Estimates Across Census Metropolitan Areas

This paper reviews alternative measures of income mixing within geographic units and applies them using geographically detailed income data derived from tax records. It highlights the characteristics of these measures, particularly their ease of interpretation and their suitability to decomposition across different levels of analysis, from neighbourhoods to individual apartment buildings. The discussion focuses on three measures: the dissimilarity index, the information theory index and the divergence index (D-index). Particular emphasis is placed on the D-index because it most effectively describes how income distributions at the sub-metropolitan level (e.g., neighbourhoods) differ from distributions at the metropolitan level (i.e., how much income sorting occurs across neighbourhoods). Furthermore, the D-index can consistently measure the contributions of income sorting within neighbourhoods (e.g., across individual apartment buildings) to the degree of income mixing at the neighbourhood and metropolitan scales.