Ludi Simpson

Statistics of Racial Segregation: Measures, Evidence and Policy

Subsequent to riots in UK northern cities, claims of self-segregation and polarised communities are examined with data unique to the city of Bradford and first results from the UK population census. Statistics relating to race often reinforce misleading stereotypes that are unhelpful to the development of appropriate social policy. Previous studies of indices of segregation are shown to be inadequate through lack of consideration of change over time and the confounding of population change with migration. The separation of natural change and migration supports survey evidence that dispersal of South Asian populations has taken place at the same time as absolute and relative growth. Social policy will do well to take on board these demographic facts in a positive inclusive approach to all residents in all areas.

Neighbourhood Effects Research: New Perspectives

Over the last 25 years a vast body of literature has been published investigating neighbourhood effects: the idea that neighbourhood characteristics can have a significant effect on residents’ life chances over and above the effect of their individual characteristics. There is little doubt that neighbourhood effects exist, but we know little about the causal mechanisms which produce them, their relative importance compared to individual characteristics, and under which circumstances and in which places these effects are important. This chapter discusses some of the main theoretical and empirical challenges in neighbourhood effects research, related to the identification of true causal effects. An over emphasis on statistical techniques to overcome the problems related to modelling selection bias had distracted us from a much more important issue: the theoretical and empirical identification of potential causal pathways behind neighbourhood effects. This chapter offers seven ways forward for neighbourhood effects research: development of clear hypotheses; empirically testing explicit hypotheses; investigating neighbourhood selection; integrate models of neighbourhood selection and models of neighbourhood effects; investigate various spatial scales; development of better longitudinal data; and the use of mixed methods research.

Combining Sample and Census Data in Small Area Estimates: Iterative Proportional Fitting with Standard Software*

Abstract The combination of detailed sample data with less detailed but fully enumerated marginal subtotals is the focus of a wide range of research. In this article we advocate careful modeling of sample data, followed by Iterative Proportional Fitting (IPF). The modeling aims to estimate accurately the interaction or odds ratios of complex tables, which is information not contained in the marginal subtotals. IPF ensures consistency with the subtotals. We advance this work in three practical ways. First, we show that detailed small-area estimates of both counts and proportional distributions usually gain accuracy by combining data for larger areas containing the small areas, and we illustrate the multilevel framework to achieve these estimates. Second, we find that a general classification or socioeconomic typology of the small areas is even more associated with the within-area interactions than is membership of the larger area. Third, we show how the Statistical Package for the Social Sciences (SPSS) can be used for IPF in any number of dimensions and with any structure of constraining marginal subtotals. Throughout, we use an example taken from the 1991 U.K. Census. These data allow us to evaluate various methods combining 100 percent tabulations and the Samples of Anonymised Records. *Census data are Crown Copyright; the 1991 Sample of Anonymised Records (SAR) s were purchased by the U.K. Economic and Social Research Council and Joint Information Systems Committee (JISC) for academic and other research purposes. The work for this paper and its writing were supported respectively by the U.K. Economic and Social Research Council awards R000223703, “Combining aggregate and micro-data to extend census tables for local areas” and RR000271214, “Local demography and race.” Paul Norman provided helpful comments on a draft.

Population dynamics: The roles of natural change and migration in producing the ethnic mosaic

This paper builds on an emerging literature that focuses on processes of population change as a means of understanding geographies of ethnicity. It argues that persistent assumptions of segregation being the result of divisive separation of ethnic groups are mistaken. The paper takes a demographic approach, presenting analyses of original estimates of natural change and net migration for eight ethnic groups in Britain over the period 1991–2001, at national and district levels. Major results are the greater significance of natural change than migration for minority ethnic population change, and the accordance of population dynamics with theories of counter-urbanisation and dispersal from areas of minority ethnic concentration. The importance of natural change is illustrated through the presentation of its effects on the index of isolation. The paper concludes that ethnic group population change in Britain can to a large extent be explained by benign and unexceptional demographic processes and ethnically undifferentiated migration patterns.

Understanding Neighbourhood Dynamics: New Insights for Neighbourhood Effects Research

Non-random sorting of residents into neighbourhoods provides neighbourhood effects researchers with a major challenge: The neighbourhoods which people ‘choose’ reflect their incomes, and as a result neighbourhood characteristics are endogenous, causing bias in models of neighbourhood effects. So understanding neighbourhood choice and neighbourhood dynamics is at the heart of a better understanding of neighbourhood effects, but is also crucial for literatures on residential mobility, segregation, and neighbourhood change. This chapter offers a state-of-the-art overview of literature on neighbourhood dynamics. First, a range of theories regarding neighbourhood dynamics are discussed. Second, the chapter offers an extensive summary of the 11 other chapters in this book, with empirical contributions from the United Kingdom, Australia, Sweden, The Netherlands, and the USA. Through this overview, this chapter offers insight into the latest developments in research on neighbourhood dynamics.

Population Dynamics in Ethnically Diverse Towns: The Long-term Implications of Immigration

Ethnically diverse urban areas are often strongly influenced by the demographic consequences of immigration. A dynamic model of population, housing and social change following immigration is proposed and then tested using a time-series of census data for northern English towns. The results show how natural growth generates dispersal of immigrant populations to new clusters. They chart the changing nature of cities and challenge the interpretation of clustering as a negative phenomenon representing retreat and separation. Instead, the focus is moved to indicators of migration, demand for housing and services, and social equality. The post-immigration demographic cycle proposed is a general one that may be tested in many other situations and countries.

Neighbourhood Effects or Neighbourhood Based Problems? A Policy Context

The introduction of this edited volume explores the links between neighbourhood effects research, perceived neighbourhood problems and the policy responses that local and national governments have pursued to ameliorate the impacts on individuals. We consider why the neighbourhood is frequently used as a site for local interventions and discuss the motivations that multiple national governments have put forward in making the case for area based policies. Previous research has been far from conclusive about how and where neighbourhood matter for individual outcomes: sometimes the neighbourhood context can be a key influence, in other cases it can appear to be relatively insignificant compared with individual characteristics. As a result, a persistent key question that regularly surfaces in discussions about neighbourhood effects and neighbourhood-based policies is whether or not place-based policies remain relevant if there is little conclusive evidence that neighbourhood effects exist. In response to this question, we suggest that even when casual neighbourhood effect are small or insignificant, there is still be a case to be made for investments in neighbourhoods to provide social facilities for communities and as an effective way to target spatially concentrated communities. However, drawing on a recent comprehensive review of place- and people-based policies in the UK there is an apparent disconnection between person- and place-based policies.

Measurement and Analysis of Segregation, Integration and Diversity: Editorial Introduction.

This editorial introduction briefly sets the context for the special issue and its constituent papers. It notes the origins of the debate in discourses of ‘parallel lives’ and ‘sleepwalking into segregation’ and highlights the inherently problematic nature both of the terminology and of attempts to measure segregation and integration. Key issues which arise from the papers which follow are highlighted.

Enhancing the Population Census: A Time Series for Sub-National Areas with Age, Sex, and Ethnic Group Dimensions in England and Wales, 1991–2001

Ethnicity data from successive censuses are used to compare population change. This paper shows that such comparisons are often impossible, wrong or misleading. Distortions become more severe as the scale of areal units becomes smaller. The paper outlines the four main sources of confusion and applies solutions for England and Wales for 1991–2001: (1) classifications, including ethnic group and age, changed between censuses; (2) non-response varies between ethnic groups, areas and ages and its treatment differs in each census; (3) the census population base changed, counting students at their home address in 1991 and at their educational address in 2001, and being taken on a different date in each year; (4) geographical boundaries used for standard census outputs changed. Each of these factors operates differentially on the outcome.

Bringing the missing million home: correcting the 1991 small area statistics for undercount

The 1991 UK Decennial Census missed about 1.2 million people. These missing individuals present a serious challenge to any census user interested in measuring intercensal change, particularly amongst the most marginalised groups in society who were prominent amongst the missing population. Recently, a web-based system for accessing census data from the 1971, 1981, and 1991 censuses was launched (www.census.ac.uk/cdu/lct). The ‘LCT’ package also provides access to a set of 1991 small area statistics (SAS) which have been corrected to compensate for the missing million. The authors explain the methods used for adjusting the SAS counts, provide examples of the differences between analysis with the adjusted and unadjusted data, and recommend the use of the new data set to all those interested in intercensal change.