Sample size determination
Power estimates were computed using approaches described by Dziak et al.When the study concluded in March 2020, a total of 1397 preschool children, nested within 113 classrooms (of 119 randomized; 95% retention) and 63 childcare centers, were enrolled; this resulted in ∼12 children per classroom and ∼7 classrooms per experimental condition. Of the 1947 parents that were recruited to participate in the parent portion of the study, 1172 consented to participate (60% participation). A total of 799 parents provided survey data (68% response rate), and 373 parents (of 541 randomized; 69% response rate) completed web-based education modules.