The ECLS-K is an ongoing study that focuses on children’s early school experiences beginning with kindergarten and following children through 12th grade. The ECLS-K data provide descriptive information on children’s status at entry to school, their transition into school, and their progression through 8th grade. The longitudinal nature of the ECLS-K data enables researchers to study how a wide range of family, school, community, and individual factors are associated with school performance. The longitudinal nature of the ECLS-K data enables researchers to study how a wide range of family, school, community, and individual factors are associated with school performance. Researchers can request the child-level files for each year of data collection, as well as the longitudinal kindergarten to fifth grade data file. Data are collected from a direct child assessment, from parent interviews, from school administrators and teachers, and from student records and a school facilities checklist.