In a classic paper, Schelling (1971) showed that extreme segregation can arise from
social interactions in preferences: once the minority share in a neighborhood exceeds a
"tipping point", all the whites leave. We use regression discontinuity methods and
Census tract data from the past four decades to test for the presence of discrete nonlinearities
in the dynamics of neighborhood racial composition. White mobility patterns
in most cities exhibit tipping-like behavior, with a range of tipping points centered
around a 13% minority share. These patterns are very pronounced during the 1970s
and 1980s, and diminish but do not disappear in the 1990s. We find similar dynamic
patterns in neighborhoods and in schools. A variety of specification checks rule out the
possibility that the discontinuity in the initial minority share is driven by income
stratification or other factors, and underscore the importance of white preferences over
neighbors ' race and ethnicity in the dynamic process of segregation. Finally, we relate
the location of the estimated tipping points in different cities to measures of the racial
attitudes of whites, and find that cities with more racially tolerant whites have higher
tipping points.

This paper presents evidence on the quality of schooling by race and ethnic
origin in the United States. Although substantial racial segregation
across schools exists, the average pupil-teacher ratio is approximately the
same for black and white students. Hispanic students, however, on average have
l0 percent more students per teacher. Relative to whites, blacks
and Hispanics are less likely to use computers at school and at work. The
implications of these differences in school quality for labor market
outcomes are examined. We conclude by examining reasons for the increase
in the black-white earnings gap since the mid-1970s.

Between 1960 and 1980 the gap in earnings between black and white
males narrowed by 15 percent. A detailed analysis of 1960, 1970, and 1980
Census data indicates that increases in the relative return to education
were largely responsible for black workers’ relative earnings gains. One
explanation for these higher returns is that they reflect the market
valuation of higher-quality schooling available to later cohorts of black
students. To investigate the role of school quality in the convergence of
black and white earnings, we have assembled data on three aspects of school
quality -- pupil/teacher ratios, annual teacher pay, and term length -- for
black and white schools in l8 segregated states from 1915 to 1966. The
school quality data are then linked to estimated rates of return to
education for men from different cohorts and states. Improvements in the
relative quality of black schools explain roughly 20 percent of the
narrowing of the black-white earnings gap in this period.

Racial segregation is often blamed for some of the achievement gap between blacks and whites. We study
the effects of school and neighborhood segregation on the relative SAT scores of black students across
different metropolitan areas, using large microdata samples for the 1998-2001 test cohorts. Our models
include detailed controls for the family background of individual test-takers, school-level controls for
selective participation in the test, and city-level controls for racial composition, income, and region. We
find robust evidence that the black-white test score gap is higher in more segregated cities. Holding
constant family background and other factors, a shift from a fully segregated to a completely integrated
city closes about one-quarter of the raw black-white gap in SAT scores. Specifications that distinguish
between school and neighborhood segregation suggest that neighborhood segregation has a consistently
negative impact but that school segregation has no independent effect (though we cannot reject equality of
the two effects). We find similar results using Census-based data on schooling outcomes for youth in
different cities. Data on enrollment in honors courses suggest that within-school segregation increases
when schools are more highly integrated, potentially offsetting the benefits of school desegregation and
accounting for our findings.