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.

This paper reexamines data from the New York City school choice program, the largest
and best implemented private school scholarship experiment yet conducted. In the
experiment, low-income public school students in grades K-4 were eligible to participate
in a series of lotteries for a private school scholarship in May 1997. Data were collected
from students and their parents at baseline, and in the Spring of each of the next three
years. Students with missing baseline test scores, which encompasses all those who were
initially in Kindergarten and 11 percent of those initially in grades 1-4, were excluded
from previous analyses of achievement, even though these students were tested in the
follow-up years. In principle, random assignment would be expected to lead treatment
status to be uncorrelated with all baseline characteristics. Including students with
missing baseline test scores increases the sample size by 44 percent. For African
American students, the only group to show a significant, positive effect of vouchers on
achievement in past studies, the difference in average follow-up test scores between the
treatment group (those offered a voucher) and control group (those not offered a voucher)
becomes statistically insignificant at the .05 level and much smaller if the full sample is
used. In addition, the effect of vouchers is found to be sensitive to the particular way
race/ethnicity was defined. Previously, race was assigned according to the racial/ethnic
category of the child's mother, and parents who marked “other” and wrote in
Black/Hispanic were typically coded as non-Black and non-Hispanic. If children with a
Black father are added to the sample of children with a Black mother, the effect of
vouchers is small and statistically insignificant at conventional levels.