Jacob, Dynarski and colleagues find very large class sizes more common for black, poor, and urban students
"Black Kids in Michigan Often Stuck in Classes With More Than 40 Kids" - The 74 Million. 11/1/2016.
Many have used classroom size as a measure of students' educational experience and of school quality. The use of student:teacher ratios, however, underestimates the number of students in core (non-specialized) classes. Brian Jacob, Rene Crespin, CJ Libassi, and Susan Dynarski analyzed administrative data from the state of Michigan to measure class size directly, along with school- and student-level characteristics. They found that, in Michigan, very large classes (40+ students) are more common for black students, and for students who receive meal subsidies and/or attend urban schools.