This study used species diversity indices developed in ecology as a measure of socioethnic diversity, and compared them to Coleman's Index of Segregation. The twelve indices were Simpson's Concentration Index ("ell"), Simpson's Index of Diversity, Hurlbert's Probability of Interspecific Encounter (PIE), Simpson's Probability of Individual Interspecific Encounter, the complement to Simpson's Concentration Index (1-"ell"), McIntosh's Index, the Shannon-Weiner Diversity Index, Number of Species (and its complement), and Importance Values (relative importance, unrelative importance, and equitability). Intercorrelation matrices were formed for racial and ethnic segregation and diversity measures. Coleman's segregation index and its expected value do not correlate strongly with each other or any of the diversity measures. Correlations approaching unity do exist between many of the racial and ethnic diversity measures. The indices using evenness, equitability, and importance of racial and ethnic characteristics to measure similarity-dissimilarity were the most effective measures of racial and ethnic diversity of schools. All the measures except Coleman's index showed public schools to be more racially and ethnically diverse than private schools. (BW)