The charter school sector is presently on the hot seat because many charter schools are highly segregated by race, and often more segregated than required by the demographics of their catchment areas. Such racial imbalance can happen when the student body of any particular school is based on a lottery among applicants to that school.  This allows for self-sorting on racial, ethnic, and other dimensions.

The principal finding is a substantive positive correlation between how friendly districts are to school choice and the degree to which their high schools are racially imbalanced for blacks and whites.

In districts with low school quality, a common application for all schools, and that provide transportation for students to schools of choice, high schools, on average, over-enroll black students.  The same conditions of choice are associated with white under-enrollment. School district choice policies are not associated with imbalance in the enrollment of Hispanic or Asian students.

To the extent that school choice as presently implemented interferes with the goal of providing students of any particular group with meaningful exposure to students from other backgrounds, choice systems could be redesigned to produce more heterogeneous student bodies.

Read the full article on segregation by Grover J. Whitehurst at Brookings