School Segregation under Color-Blind Jurisprudence: The Case of North Carolina (Working Paper)
Author(S): Charles T. Clotfelter, Helen F. Ladd, and Jacob L. Vigdor

This paper uses administrative data for the public K-12 schools of North Carolina to measure racial segregation in the public schools of North Carolina. Using data for the 2005/06 school year, the authors update previous calculations that measure segregation in terms of unevenness in racial enrollment patterns both between schools and within schools. They find that classroom segregation generally increased between 2000/01 and 2005/06, continuing, albeit at a slightly slower rate, the trend observed over the preceding six years. Segregation increased sharply in Charlotte-Mecklenburg, which introduced a new choice plan in 2002. Over the same period, racial and economic disparities in teacher quality widened in that district.

Public School Choice and Integration: Evidence from Durham, North Carolina (Working Paper)
Author(S): Robert Bifulco, Helen F. Ladd, and Stephen Ross

This paper uses evidence from Durham, North Carolina to examine the impact of school choice on racial and class-based segregation across schools. The findings suggest that school choice increases segregation. Furthermore, the effects of choice on segregation by class are larger than the effects on segregation by race. These results are consistent with the theoretical argument—developed in sociology and economics literature—that the segregating choices of students from advantaged backgrounds are likely to outweigh any integrating choices by disadvantaged students.

Teacher Credentials and Student Achievement in High School: A Cross-Subject Analysis with Student Fixed Effects (Working Paper)
Author(s): Charles Clotfelter, Helen Ladd, and Jacob Vigdor

One of the first papers to ever estimate teacher effects at the secondary school level, this groundbreaking work presents evidence that teacher credentials affect secondary school student success in systematic ways and to a significant, policy-relevant extent.

How and Why Do Teacher Credentials Matter for Student Achievement? (Working Paper)
Author(s): Charles T. Clotfelter, Helen F. Ladd, Jacob L. Vigdor

In this paper, the authors use a ten-year span of longitudinal data from North Carolina to explore a range of questions related to the relationship between teacher characteristics and credentials, on the one hand, and student achievement on the other. They conclude that a teacher's experience, test scores and regular licensure all have positive effects on student achievement, with larger effects for math than for reading. Taken together the various teacher credentials exhibit quite large effects on math achievement, whether compared to the effects of changes in class size or to the socio-economics characteristics of students.

High Poverty Schools and the Distribution of Teachers and Principals (Working Paper)
Author(s): Charles T. Clotfelter, Helen F. Ladd, Jacob L. Vigdor, Justin Wheeler

The central question for this study is how the quality of the teachers and principals in high poverty schools in North Carolina compares to that in the schools serving more advantaged students. A related question is why these differences emerge. The consistency of the patterns across many measures of qualifications for both teachers and principals leaves no doubt that students in the high poverty schools are served by school personnel with lower qualifications than those in the lower poverty schools. Moreover, in many cases the differences are large. Additional evidence documents that the differences largely reflect predictable outcomes of the labor market for teachers and principals.