The Role of Suburbanization in Metropolitan Segregation After 1940.

The three decades from 1940 through 1970 mark a turning point in the spatial scale of Black-White residential segregation in the United States compared with earlier years. We decompose metropolitan segregation into three components: segregation within the city, within the suburbs, and between the city and its suburbs. We then show that extreme levels of segregation were well established in most cities by 1940, and they changed only modestly by 1970. In this period, changes in segregation were greater at the metropolitan scale, driven by racially selective population growth in the suburbs. We also examine major sources of rising segregation, including region, metropolitan total, and Black population sizes, and indicators of redlining in the central cities based on risk maps prepared by the Home Owners Loan Corporation (HOLC) in the late 1930s. In addition to overall regional differences, segregation between the city and suburbs and within suburbia increased more in metropolitan areas with larger Black populations, but this relationship was found only in the North. In contrast to some recent theorizing, there is no association between preparation of an HOLC risk map or the share of city neighborhoods that were redlined and subsequent change in any component of segregation.

Residential Segregation under Jim Crow: Whites, Blacks, and Mulattoes in Southern Cities, 1880-1920.

We study the residential patterns of blacks and mulattoes in 10 Southern cities in 1880 and 1920. researchers have documented the salience of social differences among African Americans in this period, partly related to mulattoes' higher occupational status. Did these differences result in clustering of these two groups in different neighborhoods, and were mulattoes less separated from whites? If so, did the differences diminish in these decades after reconstruction due a Jim Crow system that did not distinguish between blacks and mulattoes? We use geocoded census microdata for 1880 and 1920 to address these questions. Segregation between whites and both blacks and mulattoes was already high in 1880, especially at a fine spatial scale, and it increased sharply by 1920. In this respect, whites did not distinguish between these two groups. However, blacks and mulattoes were quite segregated from one another in 1880, and even more so by 1920. this pattern did not result from mulattoes' moderately higher-class position. Hence, as the color line between whites and all non-whites was becoming harder, blacks and mulattoes were separating further from each other. understanding what led to this pattern remains a key question about racial identities and racialization in the early twentieth century.

Improving Estimates of Neighborhood Change with Constant Tract Boundaries.

Social scientists routinely rely on methods of interpolation to adjust available data to their research needs. Spatial data from different sources often are based on different geographies that need to be reconciled, and some boundaries (e.g., administrative or political boundaries) change frequently. This study calls attention to the potential for substantial error in efforts to harmonize data to constant boundaries using standard approaches to areal and population interpolation. The case in point is census tract boundaries in the United States, which are redefined before every decennial census. Research on neighborhood effects and neighborhood change rely heavily on estimates of local area characteristics for a consistent area of time, for which they now routinely use estimates based on interpolation offered by sources such as the Neighborhood Change Data Base (NCDB) and Longitudinal Tract Data Base (LTDB). We identify a fundamental problem with how these estimates are created, and we reveal an alarming level of error in estimates of population characteristics in 2000 within 2010 boundaries. We do this by comparing estimates from one of these sources (the LTDB) to true values calculated by re-aggregating original 2000 census microdata to 2010 tract areas. We then demonstrate an alternative approach that allows the re-aggregated values to be publicly disclosed, using "differential privacy" (DP) methods to inject random noise that meets Census Bureau standards for protecting confidentiality of the raw data. We show that the DP estimates are considerably more accurate than the LTDB estimates based on interpolation, and we examine conditions under which interpolation is more susceptible to error. This study reveals cause for greater caution in the use of interpolated estimates from any source. Until and unless DP estimates can be publicly disclosed for a wide range of variables and years, research on neighborhood change should routinely examine data for signs of estimation error that may be substantial in a large share of tracts that experienced complex boundary changes.

Models for Small Area Estimation for Census Tracts.

This study examines issues of Small Area Estimation (SAE) that are raised by reliance on the American Community Survey (ACS), which reports tract-level data based on much smaller samples than the decennial census long-form that it replaced. We demonstrate the problem using a 100% transcription of microdata from the 1940 census. By drawing many samples from two major cities, we confirm a known pattern: random samples yield unbiased point estimates of means or proportions, but estimates based on smaller samples have larger average errors in measurement and greater risk of large error. Sampling variability also inflates estimates of measures of variation across areas (reflecting segregation or spatial inequality). This variation is at the heart of much contemporary spatial analysis (Sampson 2012). We then evaluate possible solutions. For point estimates, we examine three Bayesian models, all of which reduce sampling variation, and we encourage use of such models to correct ACS small area estimates. However, the corrected estimates cannot be used to calculate estimates of variation, because smoothing toward local or grand means artificially reduces variation. We note that there are potential Bayesian approaches to this problem, and we demonstrate an efficacious alternative that uses the original sample data.

Income Segregation: Up or Down, and for Whom?

Reports of rising income segregation in the United States have been brought into question by the observation that post-2000 estimates are upwardly biased because of a reduction in the sample sizes on which they are based. Recent studies have offered estimates of this sample-count bias using public data. We show here that there are two substantial sources of systematic bias in estimating segregation levels: bias associated with sample size and bias associated with using weighted sample data. We rely on new correction methods using the original census sample data for individual households to provide more accurate estimates. Family income segregation rose markedly in the 1980s but only selectively after 1990. For some categories of families, segregation declined after 1990. There has been an upward trend for families with children but not specifically for families with children in the upper or lower 10% of the income distribution. Separate analyses by race/ethnicity show that income segregation was not generally higher among Blacks and Hispanics than among White families, and evidence of income segregation trends for these separate groups is mixed. Income segregation increased for all three racial groups for families with children, particularly for Hispanics (but not Whites or Blacks) in the upper 10% of the income distribution. Trends vary for specific combinations of race/ethnicity, presence of children, and location in the income distribution, offering new challenges for understanding the underlying processes of change.

Global Neighborhoods' Contribution to Declining Residential Segregation.

Legal and policy analysts focus on the variety of efforts to reduce racial and ethnic segregation and their impact. This study shows that independent population shifts, responding to the increasing diversity of the metropolitan population, are having large impacts that need to be taken into account. Neighborhoods where blacks and whites live in integrated settings alongside Hispanics and Asians represent a major and growing phenomenon in the United States. These "global neighborhoods" serve as an important counterweight to persisting segregation and white flight from diverse neighborhoods. In all parts of the country we show that there have substantial reductions between 1980 and 2010 in the numbers of all-white neighborhoods and corresponding growth in diverse neighborhood types.

The Spatial Scale and Spatial Configuration of Residential Settlement: Measuring Segregation in the Postbellum South.

Studies of residential segregation typically focus on its degree without questioning its scale and configuration. We study Southern cities in 1880 to emphasize the salience of these spatial dimensions. Distance-based and sequence indices can reflect spatial patterns but with some limitations, while geocoded 100% population data make possible more informative measures. One improvement is flexibility in spatial scale, ranging from adjacent buildings to whole districts of the city. Another is the ability to map patterns in fine detail. In Southern cities we find qualitatively distinct configurations that include not only black "neighborhoods" as usually imagined, but also backyard housing, alley housing, and side streets that were predominantly black. These configurations represent the sort of symbolic boundaries recognized by urban ethnographers. By mapping residential configurations and interpreting them in light of historical accounts, our intention is to capture meanings that are too often missed by quantitative studies of segregation.

The Uptick in Income Segregation: Real Trend or Random Sampling Variation?

Recent studies have reported a reversal of an earlier trend in income segregation in metropolitan regions, from a decline in the 1990s to an increase in the 2000-2010 decade. This finding reinforces concerns about the growing overall income inequality in the U.S. since the 1970s. Yet the evidence may be systematically biased to show an upward trend because the effective sample for the American Community Survey (ACS) is much smaller than it was for Census 2000, to which it is being compared. There is a possibility that the apparent changes in disparities across census tracts result partly from a higher level of sampling variation and bias due to the smaller sample. This study uses 100% microdata from the 1940 census to simulate the impact of different sampling rates on estimates of several measures of segregation and to propose and test the effectiveness of approaches to correcting the bias. It then applies those approaches to publicly available data for 2000 and 2007-2011. The reduction in sample sizes associated with the ACS results in exaggeration of evidence for increasing income segregation for all measures tested here, especially for subgroups (African Americans are studied here as an example). The methods of correction applied here will yield more conclusive and unbiased results when applied to the original sample data that is held internally by the Census Bureau.

Black Lives and Policing: The Larger Context of Ghettoization.

President Lyndon Johnson's appointment of the National Advisory Commission on Civil Disorder (Kerner Commission) followed a series of inner-city riots in the 1960s. The Commission's 1968 report, issued months before Martin Luther King, Jr.'s assassination, famously concluded that the United States was moving toward separate societies, one Black and one White. In recent years, another version of racialized violence has garnered public attention: systemic police brutality and repeated killings of unarmed Black and Brown men by police, spawning a new civil rights movement proclaiming Black Lives Matter. Condemnation of this violence and acknowledgment of its racial content by leading public officials is now standard fare, but criminal convictions and departmental discipline are scarce. This review essay brings attention back to the institutionalized racism called out by the Kerner Commission, arguing that occasional and even chronic police violence is an outcome rather than the core problem. A more fundamental issue is a routine function of policing-protecting mainstream United States from the perceived risk from its "ghetto" underbelly through spatial containment.

Racial segregation in postbellum Southern cities: The case of Washington, D.C.

BACKGROUND: Segregation in Southern cities has been described as a 20th-century development, layered onto an earlier pattern in which whites and blacks (both slaves and free black people) shared the same neighborhoods. Urban historians have pointed out ways in which the Southern postbellum pattern was less benign, but studies relying on census data aggregated by administrative areas - and segregation measures based on this data - have not confirmed their observations. METHODS: This study is based mainly on 100% microdata from the 1880 census that has been mapped at the address level in Washington, D.C. This data makes it possible to examine in detail the unique spatial configuration of segregation that is found in this city, especially the pattern of housing in alleys. RESULTS: While segregation appears to have been low, as reflected in data by wards and even by much smaller enumeration districts, analyses at a finer spatial scale reveal strongly patterned separation between blacks and whites at this early time. CONTRIBUTION: This research provides much new information about segregation in a major Southern city at the end of the 19th century. It also demonstrates the importance of dealing explicitly with issues of both scale and spatial pattern in studies of segregation.

Schools at the Rural-Urban Boundary - Blurring the Divide?

Schools mirror the communities in which they are located. Research on school inequality across the rural-urban spectrum tends to focus on the contrast between urban, suburban, and rural schools and glosses over the variation within these areas as well as the similarities between them. To address this gap and provide a richer description of the spatial distribution of educational inequality, we examine the school composition, achievement, and resources of all U.S. elementary schools in 2010-2011. We apply standard census definitions of what areas fall within central cities, the remainder of metropolitan regions, and in rural America. We then apply spatially explicit methods to reveal blurred boundaries and gradual gradients rather than sharp breaks at the edges of these zones. The results show high levels of variation within the suburbs and substantial commonality between rural and urban areas.

School Segregation and Disparities in Urban, Suburban, and Rural Areas.

Much of the literature on racial and ethnic educational inequality focuses on the contrast between Black and Hispanic students in urban areas and white suburban students. This study extends past research on school segregation and racial/ethnic disparities by highlighting the importance of rural areas and regional variation. Although schools in rural America are disproportionately white, they nevertheless are like urban schools, and disadvantaged relative to suburban schools, in terms of poverty and test performance. The group most affected by rural school disadvantage is Native Americans, who are a small share of students nationally but much more prominent and highly disadvantaged in rural areas, particularly in some parts of the country. These figures suggest a strong case for including rural schools in the continuing conversation about how to deal with unfairness in public education.

The Emerging Spatial Organization of the Metropolis: Zones of Diversity and Minority Enclaves in Chicago.

The rapid growth of Asian and Hispanic populations in urban areas is superceding traditional classifications of neighborhoods (for example as white, transitional, or minority). The "global neighborhood" that includes all groups (white, black, Hispanic and Asian) is one important new category. We examine the emerging spatial pattern of racial/ethnic composition in the Chicago metropolis, documenting an expansion of all-minority neighborhoods in the city and just beyond its borders, a shrinking set of all-white neighborhoods in the outer suburbs, and more diverse neighborhoods including whites mainly in between. The most novel element of this pattern is how large the zone of diversity has become and how far it extends into suburbia, upending the old dichotomy of "chocolate city" and "vanilla suburbs." In addition to comparing the distance of different kinds of neighborhoods from the urban core, we also analyze their adjacency to neighborhoods of the same type or other types. There is a strong tendency toward spatial clustering of each neighborhood type and also for transitions on the boundaries of clusters either to expand or to contract their territory.

Global Neighborhoods: Beyond the Multiethnic Metropolis.

Neighborhoods where blacks and whites live in integrated settings alongside Hispanics and Asians represent a new phenomenon in the United States. These "global neighborhoods" have previously been identified in the nation's most diverse metropolitan centers. This study examines the full range of metropolitan areas to ask whether similar processes are occurring in other parts of the country. Is there evidence of stable racial integration in places that lack such diversity? What are the paths of neighborhood change in areas with few Hispanic or Asian residents, or areas where Hispanics are the principal minority group, or where there is no large minority presence at all? We distinguish four types of metropolitan regions: white, white/black, white/Hispanic/Asian, and multiethnic. These regions necessarily differ greatly in neighborhood composition, but some similar trajectories of neighborhood change are found in all of them. The results provide new evidence of the effect of Hispanic and Asian presence on black-white segregation in all parts of the country.

School Segregation, Charter Schools, and Access to Quality Education.

Race, class, neighborhood, and school quality are all highly inter-related in the American educational system. In the last decade a new factor has come into play, the option of attending a charter school. We offer a comprehensive analysis of the disparities among public schools attended by white, black, Hispanic, Asian, and Native American children in 2010-2011, including all districts in which charter schools existed. We compare schools in terms of poverty concentration, racial composition, and standardized test scores, and we also examine how attending a charter or non-charter school affects these differences. Black and Hispanic (and to a lesser extent Native American and Asian) students attend elementary and high schools with higher rates of poverty than white students. Especially for whites and Asians, attending a charter school means lower exposure to poverty. Children's own race and the poverty and charter status of their schools affect the test scores and racial isolation of schools that children attend in complex combinations. Most intriguing, attending a charter school means attending a better performing school in high-poverty areas but a lower performing school in low-poverty areas. Yet even in the best case the positive effect of attending a charter school only slightly offsets the disadvantages of black and Hispanic students.

Trapped in Place? Segmented Resilience to Hurricanes in the Gulf Coast, 1970-2005.

Hurricanes pose a continuing hazard to populations in coastal regions. This study estimates the impact of hurricanes on population change in the years 1970-2005 in the U.S. Gulf Coast region. Geophysical models are used to construct a unique data set that simulates the spatial extent and intensity of wind damage and storm surge from the 32 hurricanes that struck the region in this period. Multivariate spatial time-series models are used to estimate the impacts of hurricanes on population change. Population growth is found to be reduced significantly for up to three successive years after counties experience wind damage, particularly at higher levels of damage. Storm surge is associated with reduced population growth in the year after the hurricane. Model extensions show that change in the white and young adult population is more immediately and strongly affected than is change for blacks and elderly residents. Negative effects on population are stronger in counties with lower poverty rates. The differentiated impact of hurricanes on different population groups is interpreted as segmented withdrawal-a form of segmented resilience in which advantaged population groups are more likely to move out of or avoid moving into harm's way while socially vulnerable groups have fewer choices.

Birds of a Feather: Social Bases of Neighborhood Formation in Newark, New Jersey, 1880.

This study examines the bases of residential segregation in a late nineteenth century American city, recognizing the strong tendency toward homophily within neighborhoods. Our primary question is how ethnicity, social class, nativity, and family composition affect where people live. Segregation is usually studied one dimension at a time, but these social differences are interrelated, and thus a multivariate approach is needed to understand their effects. We find that ethnicity is the main basis of local residential sorting, while occupational standing and, to a lesser degree, family life cycle and nativity also are significant. A second concern is the geographic scale of neighborhoods: in this study, the geographic area within which the characteristics of potential neighbors matter in locational outcomes of individuals. Studies of segregation typically use a single spatial scale, often one determined by the availability of administrative data. We take advantage of a unique data set containing the address and geo-referenced location of every resident. We conclude that it is the most local scale that offers the best prediction of people's similarity to their neighbors. Adding information at larger scales minimally improves prediction of the person's location. The 1880 neighborhoods of Newark, New Jersey, were formed as individuals located themselves among similar neighbors on a single street segment.

Segregation and Neighborhood Change in Northern Cities: New Historical GIS Data from 1900-1930.

Most quantitative research on segregation and neighborhood change in American cities prior to 1940 has utilized data published by the Census Bureau at the ward level. The transcription of census manuscripts has made it possible to aggregate individual records to a finer level, the enumeration district (ED). Advances in Geographic Information Systems (GIS) have facilitated mapping these data, opening new possibilities for historical GIS research. We report here the creation of a mapped public use data set for EDs in ten northern cities for each decade from 1900 to 1930. We illustrate a range of research topics that can now be pursued: recruitment into ethnic neighborhoods, the effects of comprehensive zoning on neighborhood change, and white flight from black neighbors.

Validating Population Estimates for Harmonized Census Tract Data, 2000-2010.

Social scientists regularly rely on population estimates when studying change in small areas over time. Census tract data in the United States are a prime example, since there are substantial shifts in tract boundaries from decade to decade. This study compares alternative estimates of the 2000 population living within 2010 tract boundaries to the Census Bureau's own re-tabulation. All methods of estimation are subject to error; this is the first study to directly quantify the error in alternative interpolation methods for U.S. census tracts. A simple areal weighting method closely approximates the estimates provided by one standard source (the Neighborhood Change Data Base or NCDB), with some improvement provided by considering only area not covered by water. More information is used by the Longitudinal Tract Data Base (LTDB), which relies on a combination of areal and population interpolation as well as ancillary data about water-covered areas. Another set of estimates provided by NHGIS uses data about land cover in 2001 and the current road network and distribution of population and housing units at the block level. Areal weighting alone results in a large error in a substantial share of tracts that were divided in complex ways. The LTDB and NHGIS perform much better in all situations, but are subject to some error when boundaries of both tracts and their component blocks are redrawn. Users of harmonized tract data should be watchful for potential problems in either of these data sources.

Before The Philadelphia Negro: Residential Segregation in a Nineteenth-Century Northern City.

Although some scholars treat racial residential segregation in Northern cities as a twentieth-century phenomenon, recent research on New York and Chicago has shown that black-white segregation was already high and rising by 1880. We draw on data from the Philadelphia Social History Project and other new sources to study trends in this city as far back as 1850 and extending to 1900, a time when DuBois had completed his epic study of The Philadelphia Negro. Segregation of "free Negroes" in Philadelphia was high even before the Civil War but did not increase as the total and black populations grew through 1900. Geocoded information from the full-count data from the 1880 Census makes it possible to map the spatial configuration of black residents in fine detail. At the scale of the street segment, segregation in that year was extraordinarily high, reflecting a micro-pattern in which many blacks lived in alleys and short streets. Although there was considerable class variation in the black community, higher status black households lived in areas that were little different in racial and class composition than lower status households.