The study, which was published Tuesday in the American Educational Research Association’s peer-reviewed journal, looks at a nationally representative group of more than 10,000 students who started kindergarten in 1998, tracking them every few years throughout elementary school. Controlling for a range of variables—from students’ academic performance to their socioeconomic status to their age—it aims to provide new insight into why high-performing black students are so underrepresented in gifted-and-talented programs. It turns out that the characteristics and tendencies of teachers, according to the study, could be major factors. Black students are three times less likely to be assigned to gifted-and-talented reading courses when those students are taught by non-black teachers versus black ones, the study finds. The authors argue that preventable practices and implicit biases likely contribute to this discrepancy.

In recent years, teachers have been given greater discretion in whom to refer to gifted-and-talented classes. The researchers have warned against drawing the conclusion that non-black teachers are biased against black students, and their study isn’t definitive about what’s causing the underrepresentation. They do, however, cite a number of hypotheses, including that “racialized teacher perceptions” may in part explain why educators interpret their students’ behaviors and abilities in inconsistent ways. “What a teacher may attribute to precocity for one student may be considered disruptive behavior for another,” they write. Conversely, teachers of color may recommend minority students for gifted education at higher rates. Or black teachers may simply be more effective in both motivating black students to improve their own performance and engaging with parents, who are often instrumental in getting their children screened for and enrolled in gifted-and-talented instruction.

The findings are concerning given how few classrooms are staffed with teachers of color, a problem schools have failed to address despite the increasing racial diversity of America’s schoolchildren. In fact, as The Atlantic’s Adrienne Green reported last September, a study of nine major U.S. cities including Chicago, Los Angeles, and Philadelphia found that the disparity between teachers and students of color actually increased in each of the districts between 2002 and 2012. Overall, roughly 80 percent of U.S. public-school teachers are white, and, according to the study, roughly the same percentage of black elementary-school children are taught by teachers of another race. (The vast majority of the teachers studied by the Vanderbilt researchers—91 percent—are white.) “Greater teacher diversity may help ameliorate racial gaps in student assignment to gifted programs,” Grissom and Redding write.