Researchers conducted two experimental studies to improve vocabulary knowledge and comprehension in seventh-grade social studies classes with English language learners (ELLs). The researchers randomly assigned two different, nonoverlapping samples of classes of seventh-grade students (N = 381 and N = 507) at the classroom (i.e., section) level to a social studies intervention or to business-as-usual comparison groups. Researchers assigned seven sections to treatment in experiment 1 and nine sections to treatment in experiment 2; they assigned eight sections to comparison in each experiment. In addition, researchers randomly assigned students to sections prior to assigning sections to treatment and control. Treatment students received multicomponent social studies instruction, including explicit vocabulary instruction, structured pairing, video to build concepts and promote discussion, and graphic organizers, for approximately 12 weeks daily during social studies class. Findings indicated significant differences in favor of the treatment students, including ELLs, on curriculum-based vocabulary and comprehension measures for both experimental studies.
Vaughn, S., Martinez, L. R., Linan-Thompson, S., Reutebuch, C. K., Carlson, C. D., & Francis, D. J. (2009). Enhancing social studies vocabulary and comprehension for seventh-grade English language learners: Findings from two experimental studies. Journal of Research on Educational Effectiveness, 2(4), 297–324.