S4 has been designated as the Spatial Analysis Core for the Population Studies and Training Center (PSTC) at Brown and is partly funded by the PSTC's infrastructure support grant from the National Institutes of Health . Spatial inquiry is a long-standing area of strength for the PSTC. And since its inception, S4 has relied on PSTC for administrative support, and S4 staff members have been appointed through the PSTC. Ties will be strengthened in the next several years so that S4 can more effectively technical support to individual projects that use spatial data and methods and develop new projects that incorporate spatial perspectives. A growing common interest in spatial analysis is becoming a major point of contact among demographers in different disciplines.

Migration, Social Networks, and Social Adjustment. Several scholars maintain Brown’s tradition of research on the causes and consequences of migration, including issues of migrant adjustment. Many of these studies are set in the developing regions of Africa and Latin America. David Lindstrom examines the consequences of migration in Guatemala and Mexico, and he shows how context influences individuals’ and couples’ decisions about the timing and occurrence of marriage, childbirth, and migration. His innovative project in Guatemala shows the impacts of political violence at the local level on out-migration during the insurgency of the 1970s and 1980s. Lindstrom’s current work in Ethiopia is focused on reproductive health and fertility, and examines how family and community environments lead to successful early life course transitions.

Anthropologist Dan Smith has drawn on NIH support to study the effects of migration and of the continuing ties of migrants to their places of origin on family organization, marriage, and fertility in Nigeria. In sociologist White’s research in a low-literacy African setting, event history analysis points to significant selection and adaptation effects on the fertility of migrants. Health scientist Mark Lurie focuses on the role of migration in the spread of infectious diseases, especially HIV/AIDS, in Southern Africa. It is not simply migrant men who return home to infect their rural partners, but in fact some women become infected prior to their husbands and long-term partners. Leiwen Jiang and Michael White are analyzing the role of occupational selectivity in recent Chinese migration.

Population researchers have also given attention to migration and immigration in the United States. Sociologist John Logan has conducted a series of studies on immigrants’ access to community resources, home ownership, and labor market position, demonstrating that race and ethnicity are stronger determinants than generation or years in the U.S. White has used panel data to model immigrant achievement and family formation in early adulthood, finding that academic trajectories of the first and second generation differ only modestly from others once background factors are controlled. Economist Rachel Friedberg uses the 1960-2000 U.S. Census microdata (PUMS) to study changes over time in the labor market performance of immigrants in the United States. She finds that immigrants who came to the U.S. in the late 1990s experienced greater labor market success than did earlier cohorts upon arrival.

Urbanization. Population researchers at Brown also examine the growth and structure of cities themselves, both in the United States and elsewhere, with attention to the impacts on the resulting economies, labor markets, and local public services. In his recent work, economist Vernon Henderson has studied the interactions between rural-urban migration, city growth, democratization, and technological progress. He has also analyzed the effects of China’s migration restrictions on the productivity and efficiency of cities. Economist Nancy Qian has also conducted studies of the Chinese urban setting, including the effect of infrastructure on economic growth, and the effect of tax and fee reform and the effect of rural-urban migration on rural areas. Logan continues research on urban development and housing issues in China as founder of the Urban China Research Network, and he is now using new survey and census data to analyze Chinese suburbanization. Economist Nate Baum-Snow raises similar questions in the context of the United States, evaluating the effects of highway construction and new fixed rail transit on suburbanization. Others are analyzing the development of ethnic labor markets in urban areas. Logan has used both historical and contemporary census data to document the emergence of enclave economies in U.S. cities and to evaluate their impacts on ethnic labor force outcomes. Logan, Baum-Snow, and others plan a joint project on the effects of court-ordered desegregation on whites’ residential choices. Economist Mark Pitt is planning an impact evaluation of the Egypt Social Fund for Development (SFD), using local variation in infrastructure investment to test whether policy has had an impact on income-generating activities.

Neighborhood effects. Several studies represent PSTC scholarly interest in how local conditions affect individual and group outcomes. Kaivan Munshi has focused on how informal community-based networks facilitate economic activity in developing economies in studies of emigration from Mexico, access to capital in India, and finding jobs in Kenya. Susan Short takes advantage of spatial variation in policy to show that the one-child policy, as locally implemented, continues to suppress fertility in China. Qian has studied the effect of pollution tariffs on air emissions and infant mortality, and plans to extend this line of work to investigate the long-run health effects of arsenic exposure in Inner Mongolia. Glenn Loury, an economist, will join John Tyler from education and other social science associates to examine the interconnections among neighborhood segregation, school ethnic concentration, and educational achievement.

Spatial methods. Reflecting increased reliance on spatially referenced data, PSTC researchers are dealing with new methodological questions and developing new datasets. Logan is working with data from the 1880 Census of Population to create summary data files and GIS maps of major U.S. historical urban centers. The project will provide public-use data and form the basis for Logan’s own comparative analyses of residential segregation and ethnic labor markets in 30 cities. Baum-Snow grapples creatively with urban economic geography and demonstrates methods to merge census data with data from the Bureau of Transportation Statistics on the location of transportation infrastructure and Census Transportation Planning Package (CTPP) data on the location of employment by industry. Naresh Kumar is developing innovative methods of measuring air pollution at a high spatial-temporal resolution to impute long-term personal exposure to fine particulate matter (PM2.5). Logan is finding new uses for information on spatial autocorrelation to tackle the well-known Modifiable Areal Unit Problem, arguing that spatial clustering can be used to define appropriate geographic areas for study. White continues to evaluate alternative concepts and measures of residential segregation, addressing problems of panethnicity and using census-simulated microdata to more accurately assess spatial clustering. Joseph Hogan (in Community Health) has developed a new factor-analytic approach to characterizing spatial variation in social class, and continues to work with White on drawing inferences about immigrant assimilation in the face of missing information from panel data.