We investigate the impact of a relatively brief cross-curricular intervention, Word Generation, on middle school students' development of taught academic vocabulary. Students (n = 8382) in forty-four middle schools in three urban districts were randomly assigned to treatment or control conditions. Treatment teachers implemented the program with…

The purpose of this replication study was to examine the impact of the Teacher Study Group (TSG) professional development in vocabulary on first-grade teachers' knowledge of vocabulary instruction and observed teaching practice, and on students' vocabulary knowledge. Sixty-two schools from 16 districts in four states were randomly assigned to…

Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led…

A multi-cohort cluster randomized trial was conducted to estimate effects of rich vocabulary classroom instruction on vocabulary and reading comprehension. A total of 1,232 fourth- and fifth-grade students from 61 classrooms in 24 schools completed the study. Students received instruction in 140 Tier Two vocabulary words featured in two…

The purpose of this varied replication study was to evaluate the effects of a supplemental reading intervention on the beginning reading performance of kindergarten students in a different geographical location and in a different instructional context from the initial randomized trial. A second purpose was to investigate whether students who…