The Goal 3 Efficacy Study examines the impact of RULER, a widely-used, whole-school social and emotional learning (SEL) intervention, compared to a business-as-usual counterfactual. The study examines the impact of RULER implemented in ideal conditions on school climate and teacher well-being, classroom climate, and students’ social and emotional skills and academic outcomes across students in grades 1-5. This study will result in “evidence regarding the impact of a fully developed intervention on relevant student education outcomes relative to a comparison condition using a research design that meets the Institute’s What Works Clearinghouse evidence standards.”