A recently released study that looks at the effects of an influx of African-American students into various schools within an urban North Carolina school district is raising some interesting questions about patterns of teacher movement.
The study by C. Kirabo Jackson, an associate professor of labor economics at Cornell University, shows that the highest quality teachers in the Charlotte-Mecklenburg school district left their schools after a long-running busing policy to promote integration was ended. Jackson's study, published in the Journal of Labor Economics, tracked the changes that occurred before and after the busing policy ended between 2002 and 2003. Because the racial makeup of the schools changed suddenly but the neighborhood and economic factors overall stayed the same, the research was able to focus directly on the impact the student body itself had on teacher quality.
"This is particularly sobering because it implies that, all else equal, black students will systematically receive lower-quality instruction," says Jackson. "This relationship may be a substantial contributor to the black-white achievement gap in American schools."
Using data from the North Carolina Education Research Data Center, Jackson found that schools that had an increase in black enrollment saw a decrease in their share of high-quality teachers, as measured by years of experience and certification test scores. Teacher effectiveness, as measured by teachers' ability to improve student test scores, also went down in the schools with an inflow of black students. The change in teacher quality generally occurred when the busing program ended, indicating that teachers moved in anticipation of more black students.
It is unclear whether the teacher-movement patterns in the 137,000-student Charlotte-Mecklenburg district would be typical of other large, urban school systems. A growing body of research does show that schools in low-income areas with high concentrations of minority students tend to have teachers who are considered, on average, to be of a lower quality than those in more affluent areas. And plenty of studies document how common it is for teachers to move from shaky, high-needs schools to better-performing suburban schools.
But it is almost impossible to pin down the reasons why some teachers stay away from, or leave, struggling schools. Is it out of convenience to be closer to their own suburban homes? Better pay? A desire to teach students from a particular background or of a particular ethnicity? In an interview with Education Week, Jackson says his study might offer a handle on those questions.
"An important implication of these findings is that policymakers should be cautious when advocating policies such as vouchers, school choice, district consolidation, or school busing that require the reshuffling of students across schools," the study concludes, because shifts in student population might lead to shifts in teacher quality.