This study examined whether placing sixth graders in middle schools rather than elementary schools affects their behavior and academic performance.
Sixth graders in middle schools were about twice as likely to have a disciplinary infraction as sixth graders in elementary schools. Sixth graders in middle schools also had lower scores on standardized reading tests than sixth graders in elementary schools. There were no statistically significant differences in math test scores.
Cook, P. J., MacCoun, R., Muschkin, C., & Vigdor, J. (2008). The negative impacts of starting middle school in sixth grade. Journal of Policy Analysis and Management, 27(1), 104–121.