Racial Composition and Occupational Segregation and Inequality across American Cities Moshe Semyonov, Yitchak Haberfeld, Yinon Cohen, and Noah Lewin-Epstein Department of Labor Studies, Tel-Aviv University, Tel-Aviv, Israel The major purpose of the present research is to estimate and compare several measures of race– occupational differentiation across American cities and to examine their relation- ships to structural and compositional characteristics of cities, especially to the size of the Black population. Using the 1990 PUMS for American cities (MSAs), we estimated measures of nominal segregation and ordinal inequality that were used in past research. The measures used in our analysis include the index of dissimilarity, size standardized index of dissimilarity, index of net differences, and the ratio index that was proposed recently in the literature. The findings reveal considerable differences between the standardized and unstandardized measures. The meaning of the findings and their impli- cations for theoretical conclusions are discussed. © 2000 Academic Press Researchers in the human ecology tradition have long studied the relationship between the structural characteristics of the labor market and inequality. Studies in this tradition employed a variety of measures to estimate the rate of occupa- tional inequality between the races. The most widely used measures of inequality have been the index of dissimilarity (Duncan and Duncan, 1955; Gibbs, 1965) and the index of net differences (Lieberson, 1975). Recently, Charles (1992) and Charles and Grusky (1995) introduced a new measure of occupational differen- tiation—ratio index—which is computed within the log-linear framework. 1 Although the various indices were designed to measure occupational inequal- ity, each captures a somewhat different dimension of occupational differentia- tion. Whereas the index of dissimilarity and the ratio index pertain to nominal segregation irrespective of occupational ranking, the index of net differences measures hierarchical differentiation in a rank-ordered occupational system (Fos- sett, 1984; Fossett and South, 1983; Fossett et al., 1989; James and Taueber, 1985; Charles and Grusky, 1995). Since the indices capture different aspects of Address correspondence and reprint requests to Moshe Semyonov, Department of Labor Studies, Faculty of Social Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel. E-mail: moshes@post.tau.ac.il. 1 The ratio index was applied by Charles and Grusky to estimate gender– occupational differenti- ation. Indeed, it can be used to estimate race and occupational differentiation as well. Social Science Research, 29, 175–187 (2000) doi:10.1006/ssre.1999.0662, available online at http://www.idealibrary.com on 175 0049-089X/00 $35.00 Copyright © 2000 by Academic Press All rights of reproduction in any form reserved.