Children's academic experiences during first grade have substantial implications for their academic performance both concurrently and longitudinally. Using two complementary studies, this dissertation utilizing data from the National Institute of Child Development Study of Early Child Care and Youth Development helps create a better understanding of the importance of first-grade experiences for children's academic performance. The first study expands upon current literature by focusing on how children's academic experiences simultaneously influence children's academic performance through behavioral engagement. Specifically, study one examined the mediating role of first-grade behavioral engagement between first-grade academic experiences (i.e. parental involvement, positive peer interactions, student-teacher relationship, and instructional support) and second-grade academic performance. Using a panel model, results showed that behavioral engagement mediates relations between peer interactions and academic performance and relations between instructional support and academic performance. Implications for interventions focusing on children's positive peer interactions and teacher's high-quality instructional support in order to promote behavioral engagement during early elementary school are discussed.

The second study expands the current literature regarding instructional quality thresholds. Limited research has addressed the question of whether there is a minimum level of instructional quality that must be experienced in order to see significant changes in children's academic performance, and the limited research has focused primarily on preschoolers. The goal of study two was to determine if high-quality first-grade instructional support predicted children's first-, third-, and fifth-grade academic performance. Using piecewise regression analyses, results did not show evidence of a relation between first-grade instructional support quality and children's academic performance at any grade. Possible reasons for inconsistencies in findings from this study and previous research are discussed, including differences in sample characteristics and measurement tools. Because instructional quality remains at the forefront of discussions by educators and policy makers, the inconsistencies in research findings argue for further research that may clarify thresholds of instructional support quality that must be met in order for various subgroups of children to gain the skills needed for long-term academic success.