parental choice and segregation: evidence from the united states helen f. ladd [email protected]...
TRANSCRIPT
Overview
• Evidence from countries around the world supports the conclusion that when parents are empowered to choose schools, education systems tend to be more segregated by race and/or SES than would be the case without parental choice.
• In this talk I use two case studies from the state of North Carolina to explore some of the motivations and mechanisms through which that outcome occurs.
References for this talk• R. Bifulco and H. F. Ladd. 2007. “School choice, racial segregation,
and test score gaps: Evidence from North Carolina’s charter school program.” Journal of Policy Analysis, 26 (1): 31-56.
• R. Bifulco, H.F. Ladd, and S. Ross. 2009. “Public school choice and integration: Evidence from Durham, North Carolina.” Social Science, 36 (1):71-85.
Related articles R. Bifulco and H.F. Ladd, 2006.”The impact of Charter Schools on Student Achievement: Evidence from North Carolina.” Journal of Education Finance and Policy, 1(1): 50-90.
C.T. Clotfelter, H.F. Ladd, and J.L. Vigdor. 2008. “School segregation under color-blind jurisprudence: The case of North Carolina.” Journal of Social Policy and the Law. 16 (1).
North Carolina (NC)
A southern state, with population over 9 million.
-- 31 percent of all students are African American (black) and about 5 percent are Hispanic (but growing rapidly). -- Prior to the late 1960s, schools were almost completely segregated by race. -- More recently, however, school segregation by race in NC has been relatively low by U.S. standards – but now some evidence of resegregation.
2 examples -- both from NC1. Charter schools -- schools of choice 2. Choice in multiple forms in Durham, N.C.
North Carolina Data
• Longitudinal data for students over time => We can follow students as they move from school to
school.
• Test scores for all students in grades 3-8 reading and math 1996-2002 (5 cohorts of students)
=> We can estimate value-added achievement models with student fixed effects.We cannot follow students before grade 3
• Data set includes students in traditional public schools and charter schools
Does not include students in private schools.
First example: NC Charter Schools
• Def of a charter school: -- A publicly funded school not operated by the government -- Needs a charter to operate; can be shut down if it doesn’t meet the requirements of the charter. -- School of choice. No assigned students.
• NC Enabling legislation (1996) – Cap of 100 schools – Moderately permissive compared to other states– Same operating funding for charter schools as for traditional
public schools – Among the goals: to expand schooling options--especially for
minority and poor children.
Racial considerations
Initial concern was that charter schools might serve primarily white or advantaged students. Response of policy makers:
-- Legal requirement: racial mix of charter school in line with racial mix in the district-- Charters easier to obtain if they served disadvantaged students.
In practice, black students are overrepresented in charter schools and many charter schools are predominantly black (30 schools > 80 percent black) Next two slides look at the changes in peer groups for black and white students who move to charter schools.
Changes in peers for black students
who move to a charter school (1918 students) Charter Traditional
public schoolAverage
Change
Fraction Black
0.702 0.534 0.168
Fraction college ed. parents
0.306 0.279 0.027
Average math score (sd, lagged)
-0.510 -0.134 -0.376
Changes in peers for white students who move to a charter school (2714 students)
Charter Traditional public school
Average
Change
Fraction Black
0.180 0.294 -0.114
Fraction college ed. parents
0.474 0.347 0.127
Average
math score
(sd, lagged)
0.183 0.098 0.085
Why Do So Many Black Students Choose Racially Segregated Charter Schools?
Three possibilities
1. Those schools offer a higher quality education
2. Black students want to attend a school with students of their own race (neutral ethnocentrism)
3. Outcome does not reflect their preferences alone.
Possibility 1: To obtain higher quality education
Not consistent with the simple data – black students move to charter schools with lower achievement than the public school they left. But note that that describes the student intake – and says nothing about school effectiveness.
=> Need to look more carefully at how charter schools affect student achievement.
Effects Of Charter Schools
on Student Achievement • Model: Gain in achievement = f(CH, other
variables) -- based on individual students.
• Preferred model – Includes student fixed effects => gains for
students in charter schools are measured relative to gains for those very same students when they were in traditional public schools
– Includes control variables for change to a new school, structural and non structural
Estimated impacts of charter school
attendance on math achievement • Average -0.160 (standard deviations)
(i.e. average effect is negative)
• White students : -0.130
• Black students: -0.190
Conclusion. Charter schools reduce achievement on average, and even more for black students than for white students.
Achievement effects (cont.) Moreover, achievement most adversely affected for black
students who make racially segregating moves when they switch to a charter school.
• White student -0.126• Black student-non racially segregating move -0.127 (no different
from white)• Black student making a racially segregating move -0.225
Definition of racially segregating move: movement to a charter school that is more than 60 percent black and with a percent black 10 or more percentage points higher than the public school from which the student transferred.
Conclusion: This evidence not consistent with the conclusion that black switchers are choosing schools that are more effective in raising achievement.
Possibility 2: Black students prefer schools that serve mainly black students.
To examine this possibility, we estimate a conditional logit model for black students of the following form:
Probability of choosing a particular charter school = f (racial profile of the school, and accessibility of the school)
Where: Racial profile is defined by categories of the school’s percentage of black
students. i.e. <,20, 20-40, 60-80,>80. Base category is 40-60.
Model is conditional on having chosen a charter school, and is estimated just for black students in one of the state’s 5 metro areas who have more than one choice of charter school within 10 miles
Conclusion: Black switchers prefer charter schools that are 40-60 percent black.
Possibility 3. Outcomes do not reflect black preferences alone
In fact there are very few charter schools with a racial mix that is 40-60 percent black.
Why so few of those schools?Answer: whites prefer schools that are less than 20 percent black -- based on a conditional logit choice model for white charter school students.
Conclusions about charter schools
1. Charter schools in North Carolina– increase segregation– increase the black-white test score gap
2. Racially isolating charter schools generate larger negative effects on student achievement than other charter schools
3. Segregation in charter schools reflects asymmetric preferences
– Blacks appear to prefer charter schools with 40-60 percent black students
– Whites prefer charter schools with less than 20 percent black students
Example 2: Choice in Durham, NC
Exploration of differential preferences by race and SES from a broader perspective.
Situation in Durham (Population: 222,000, 60 percent black students in elementary and middle schools)
Geographic school assignment zones designed to promote integration.
Many choice options -- Easy transfers between zones. -- Magnet schools – intended to attract white students to
schools in black areas (Middle school magnets more like true magnets than those at the elementary level)
-- Charter schools -- Year round schools
Conceptual considerations related to parental preferences
• Preferences based on race and class mix of students in a school.
Outgroup avoidance – advantaged group tries to avoid the minority group
Neutral Ethnocentrism – both groups prefer schools with pupils similar to themselves.
Liberation theory – school choice makes it possible for families to choose schools more integrated than their residential neighborhoods.
But in addition, need to consider preferences related to school quality.
Preferences (cont.)
• Preferences related to school qualityAll groups typically value school quality, but quality determined both by the quantity and quality of school resources and by the profile of students in the school. => Advantaged students: desire for school quality often reinforces preferences related to race and SES of students. That is clearly the case when school resources are positively correlated with the proportion of advantaged students in the school. => Disadvantaged students may face a trade-off.
Empirical Strategy
• Test 3 hypotheses -- based on plausible assumptions about the distribution of preferences (which we cannot examine directly).
• Both elementary (grades 3-5) and middle schools (grades 6-8).
• Attention to segregation by race and by class (as measured by education level of the students’ parents).
Hypothesis 1
Advantaged students (white and/or those with college educated parents) will use school choice to avoid schools with disadvantaged students
Motivation. Some combination of outgroup avoidance, neutral ethnocentrism, and preference for high quality schools. Note that the motivations reinforce each other in this case.
Evidence – based on a linear probability
model of opting out of the assigned zone • Whites – a 10 percentage point higher
proportion of black students in the assigned school zone increases the probability of opting out by 5.7 percent at the primary level and 11.23 percent at the middle school level.
• College educated parents – a 10 percentage point lower proportion of college educated parents in the assigned zone increases the probability of opting out by 9.3 percent at the elementary level and 23.4 percent at the middle school level.
=> Hypothesis is supported
Hypothesis 2
Disadvantaged students (black and/or those with parents with no college) will be more likely than advantaged students to use choice to make integrative moves.
Logic – unlike the advantaged students for whom all the incentives tend to work in the same direction, disadvantaged students face a trade off. Desire for school quality (which may be determined in part by presence of advantaged students) vs. preferences to be with students similar in race or SES to themselves.
Next two slide provides strong support for this hypothesis.
Evidence on integrating moves by race (percent of students)
Integrating move
Segregating move
Grades 3-5
White 5.9
Black 10.9
Grades 6-8
White 8.4
Black 9.5
Evidence on integrating moves by education of parents (percent of students)
Integrating moves
Segregating moves
Grades 3-5
College 6.5
No college 14.3
Grades 6-8
College 4.1
No college 11.3
Hypothesis 3
The net effect of parental choices will be to increase segregation by race and class relative to geographic assignment policies.
Logic – Especially true when geographic assignments are designed to promote integration. Both groups will make segregating moves, with advantaged groups making them more frequently. We expect the net segregating effects of choices made by advantaged groups to offset any integrating effects of choice made by disadvantaged students.
See the next 2 slides for segregating moves relative to integrating moves.
Evidence on segregating moves by race (percent of students)
Integrating move
Segregating move
Grades 3-5
White 5.9 16.4
Black 10.9 18.4 (higher than predicted)
Grades 6-8
White 8.4 12.7
Black 9.5 14.2 (higher than predicted)
Evidence on segregating moves by education of parents
(percent of students)
Integrating moves
Segregating moves
Grades 3-5
College 6.5 22.0 (note size)
No college 14.3 12.9
Grades 6-8
College 4.1 32.5 (note size)
No college 11.3 10.4
Other evidence on net segregation effects
Comparisons of actual measures of segregation in 2002/03 to those that would have emerged if all students had attended schools in their assigned geographic zones.
Isolation and exposure indices. Examples.
-- An isolation index for blacks denotes the percentage of black students in the school of the average black student.-- An exposure index for blacks denotes the percentage of white students in the school of the average black student.
Cautionary point. The counterfactual is not the same as what we would see if there were no choice programs If no choice, families might distribute themselves differently across neighborhoods, policy makers might define different geographic school zones, and more families might opt for private schools.
Compared to the counterfactual, the average differences by race are small,
but loom large in some cases Grades 3-5.
Both blacks and whites are slightly more isolated; and each has slightly less exposure to the other group.
Grades 6-8. Blacks no more isolated; each group has slightly
less exposure to the other group.But big differences in the tails:
--Much higher proportion of black students (grades 3-5) in schools with more than 75% black students (28 % v. 18 %).-- Much higher proportion of black students (grades 6-8) in schools with more than 90 % black (7 % vs. 4%).
Average differences associated with the choice programs are larger
by SES than by raceCompared to the counterfactual:
Students with highly educated parents have far higher exposure to students with highly educated parents at both grade levels.
Students with undereducated parents have far higher exposure to student with undereducated parents at both grade levels.
Conclusions about choice programs in Durham
• True that parental choice makes possible some integrating moves.
• But segregating moves outweigh the integrating moves.
• The net effects on segregation relative to the counterfactual in this context are larger by SES than by race.
Conclusion
Choice programs are likely to generate segregated schools.
But useful to sort out the motivations and mechanisms through which parental choice programs generate segregation if we want to design policies to keep choice-related impacts on segregation to a minimum.