Rethinking the Analysis of Ethnic Residential Patterns: Segregation, Isolation, or Concentration Thresholds in Auckland, New Zealand?
Johnston, Ron, Poulsen, Michael, Forrest, James, Geographical Analysis
Data from the 1996 New Zealand Census on ethnicity in Auckland Urban Area are used to illustrate a new approach to measuring spatial separation. The traditionally employed single-number indices are found wanting and a method based on thresholds is introduced. This provides more detailed information on the geography of ethnic groups that is consistent with the requirements for testing hypotheses regarding the relationship between social and spatial distance. The results show that (with a few exceptions) Polynesian groups were more encapsulated groups in Auckland than were Asian and European groups, and that most of the European groups--along with the "host society," the New Zealand Europeans--were not spatially exposed to members of the Polynesian and Asian groups.
After decades of debate on the nature of residential segregation and how to measure it, research has tended to lapse into a degree of theoretical, methodological, and even terminological uncertainty, associated with the promotion of a variety of different definitions and measures (Massey and Denton 1988, p. 282). Consistency and comparability certainly, and potentially the validity of the research area itself, all suffer as a result. None of this is satisfactory at a time of burgeoning interest in the social dynamics of plural, ethnically heterogeneous cities (Grillo 2000) or EthniCities (Roseman, Laux, and Thieme 1996). In particular, established relationships between ethnic residential patterns and social distance from the host society, through the operation of the housing market, bear on issues of social discrimination and exclusion, and of economic disadvantage, as well as positive reasons for ethnic group segregation associated with retention of cultural identity. Hence the continuing need, not only to continue the debate about theories of the nature and dynamics of ethnic group concentration in urban areas, but also to develop methodologies that can accurately map and describe the social geographies of ethnic groups in light of developing theory. This paper examines several major aspects of the methodological debate, looking especially at the indexes of segregation and isolation and at a new, threshold analysis methodology, in the context of recent developments to the theorization of the nature and dynamics of ethnic group concentrations. The case study application is to Auckland, New Zealand's largest and arguably best example of a modern EthniCity.
MEASURING ETHNIC GROUP CONCENTRATION
Two important issues regarding the measurement of ethnic group concentrations center on the use of single index values and comparability over time and space. Although many researchers have adopted a single index approach to the measurement of ethnic concentrations, in fact this oversimplifies the situation. Massey and Denton (1938, 1989) identified at least five main and largely independent dimensions of segregation, each with its own index or set of indexes. The most well known of these dimensions is identified as evenness (or difference), measurement of which is associated with the Index of Dissimilarity (ID) and the related Index of Segregation (IS: Duncan and Duncan 1955; see also Taeuber and Taeuber 1965). Both are relative measures of the difference between the distribution of one population group compared with another across the constituent parts of an urban area: with the ID, the comparison is between two groups within the population; the IS contrasts the distribution of one group with that for the r emainder of the population.
However, because the evenness dimension, along with those of concentration (the amount of physical space occupied by a minority group), centralization (the degree to which an ethnic group is spatially concentrated near the center of a city), and clustering (the distribution of ethnic groups relative to each other), are relative measures, the patterns they describe are unique to each city. …