ECLS data can be used to measure children's skills and knowledge at several intervals from birth through eighth grade. Transitions that can be analyzed using the ECLS program data include the transition that occurs as young children first receive care and education on a regular basis from persons other than their parents, as well transitions to group-based early childhood programs and other forms of nonparental care and education, and from preschool to kindergarten.

Children enter kindergarten with differing levels of preparation for school and performance. For some children, the first formal school experience is kindergarten. The studies examine children's preparation for school by studying the different characteristics of children, their families and home learning activities, and their nonparental care and early educational experiences. Issues that the ECLS program studies focus on include the status of children at entry to kindergarten; the expectations of parents and schools about what skills, behaviors, and attributes are necessary for school success; and how children fare in the new environment as they make the transition from home to school. Parents' definitions of school readiness (i.e., what beliefs and standards they have for children's behavior and academic performance at entry into kindergarten) can be analyzed, as well as how definitions of readiness differ by parental background characteristics.

Schools and classrooms play a critical role as learning environments in promoting children's positive outcomes. The ECLS program studies provide useful information on how schools and classrooms address the needs of all children, including those with particular needs (e.g., due to limited English proficiency or disabling conditions). The studies collected data on how well children perform in different kinds of classrooms and schools and on the interaction between children's backgrounds and their performance in different learning settings. For example, children's competencies in domains such as language and executive function can be examined, as well as how children's development of and growth in these competencies varies by child and family social, demographic, and contextual characteristics. Data were collected on curriculum, instructional practices, resources, school climate, and background characteristics of teachers and administrators in order to examine the relationship between these factors and children's school performance over time. Additionally, data are available to investigate how teachers and schools address the diversity of children's skills and how children with particular needs (e.g., English language learners, gifted and talented students, students with Individualized Education Programs for children with disabilities) are taught.

Numerous factors influence children's educational and other life outcomes. The studies provides critical information on the roles that parents and families play in preparing for and supporting their children's education and how families, schools, and communities interact to support children's education. The ECLS program studies focus on the resources of the family, the home environment, and the community that can have a profound impact on children's success in school and provide the context within which schools must operate. For example, analysts can use ECLS data to examine how family processes, parenting practices (e.g., home environment, family activities, and cognitive stimulation), and parent involvement in their child's schooling relate to children's school readiness, developmental status, and adjustment. Similarly, data were collected to analyze what kinds of services or programs schools provide to families, children, or community members and how these relate to children's development.