“…Given the large variation in vocabulary size and growth trajectories that have been identified within the United States and Latin American countries, and which are highly correlated with and predicted by SES (Fernald et al., ; B. Hart & Risley, ; Hoff, ; Rowe, Raudenbush, & Goldin‐Meadow, ; Schady, , ), we seek vocabulary interventions that are equally or more effective for students who start out behind. A few program evaluations, including one in Chile, have considered variation in impacts of programs including explicit vocabulary instruction, and some, but not all, have found greater effects for students with poorer vocabularies (Hamre et al., ; Hindman, Erhart, & Wasik, ; Pallante & Kim, ). Therefore, it is important to better understand not just which types of classroom instruction are more effective in supporting vocabulary growth but also what works for whom.…”