Attewell, P., Lavin, D., Domina, T., & Levey, T. (2006). New Evidence on College Remediation. The Journal of Higher Education, 77(5), 886-923.
Using college transcripts, the authors separate the effects of remedial coursework from high school preparation. For two-year colleges, the completion of remedial classes was not associated with less academic success. In four-year colleges, there are negative effects of remedial coursework, but many minority students who complete a bachelor's degree do so after taking remediation.