The purpose of this study was to deepen the evidence base for interventions that support the social-emotional skills that underlie children's engagement and attention to learning tasks by schools (learning behaviors) and their social interactions with teachers and peers (social behaviors). The study tested three theoretically-distinct approaches to enhancing children's social-emotional development, along with a comprehensive coaching and training model, on a large scale within the Head Start system.

Inclusion Criteria:

• Grantees had to have at least 4 centers with a similar racial/ethnic composition
• An equal number of classrooms with full-day or part-day programs
• And a similar mix of four-year-old-only and mixed-age (three-and four-year-old) classrooms.
• Children had to speak English and Spanish.

Exclusion Criteria:

• A grantee was excluded from the sample if it: only ran early Head Start programs
• Only served migrant children
• Was located in a U.S. territory
• Only or mostly provided family child care or home services
• Was more than 100 miles from a "primary airport,"
• Operated fewer than 4 centers with two classrooms each
• Had been in operation for less than 2 years
• Was not in compliance with Head Start Standards
• They were already systematically implementing a social-emotional curriculum or participating in another evaluation study.