The Black–White achievement gap has often been studied, but its relationship to school composition has generally not been explored. The demographic makeup of public schools is of particular interest, given recent concerns about the growing resegregation of schools. This report explored eighth-grade achievement as it relates to the percentage of students in the school who were Black, or the density of Black students, to contribute to the understanding of the Black–White student achievement gap. The data used to explore these relationships came primarily from the National Assessment of Educational Progress (NAEP) 2011 Mathematics Grade 8 Assessment but also from the Common Core of Data for 2010–11, which provided additional school characteristics.

Analysis of the relationship between the percentage of students in a school who were Black and achievement showed the following:

• Achievement for both Black and White students was lower in the highest Black student density schools than in the lowest density schools.
• However, the achievement gap was not different.

However, when accounting for factors such as student socioeconomic status (SES) and other student, teacher, and school characteristics, the analysis found:

• White student achievement in schools with the highest Black student density did not differ from White student achievement in schools with the lowest density.
• For Black students overall, and Black males in particular, achievement was still lower in the highest density schools than in the lowest density schools.
• The Black–White achievement gap was larger in the highest density schools than in the lowest density schools.
• Conducting analysis by gender, the Black–White achievement gap was larger in the highest density schools than in the lowest density schools for males but not for females.