He found that within schools, black and white students were treated similarly, but that student disciplinary outcomes varied significantly across schools. (prospect.org)
Comparing students to themselves over time effectively controls for all student characteristics that do not change over time and could lead to differences in disciplinary outcomes. (educationnext.org)
Of course, race is not the only aspect of the match between students and teachers that could influence disciplinary outcomes; gender could also matter. (educationnext.org)