Gregory, A., Skiba, R. J., & Noguera, P. A. (2010). The achievement gap and the discipline gap: Two sides of the same coin? Educational Researcher, 39(1), 59-68.

The gap in achievement across racial and ethnic groups has been a focus of education research for decades, but the disproportionate suspension and expulsion of Black, Latino, and American Indian students has received less attention. This article synthesizes research on racial and ethnic patterns in school sanctions and considers how disproportionate discipline might contribute to lagging achievement among students of color. It further examines the evidence for student, school, and community contributors to the racial and ethnic patterns in school sanctions, and it offers promising directions for gap-reducing discipline policies and practices.

Full article can be found here: http://journals.sagepub.com/doi/abs/10.3102/0013189X09357621