The Early Childhood Longitudinal Study, Kindergarten Class of 1998–99 (ECLS-K) was designed to provide detailed information on children's early school experiences. The study began in the fall of 1998. A nationally representative sample of 21,300 children enrolled in 940 kindergarten programs during the 1998–99 school year was selected to participate in the ECLS-K. The children attended both public and private kindergartens, and full-day and part-day programs. The sample included children from different racial/ethnic and socioeconomic backgrounds and oversamples of Asian and Pacific Islander children and private school kindergartners. Base-year data were collected in the fall and spring of the kindergarten year. Data were collected again in the fall of first grade in 1999 (from a 30 percent subsample of schools) and the spring of first grade in 2000, and then in the spring of third grade in 2002, the spring of fifth grade in 2004, and the spring of eighth grade in 2007.
From kindergarten to fifth grade, the ECLS-K included a direct child cognitive assessment that was administered one-on-one with each child in the study. The assessment used a computer-assisted personal interview (CAPI) approach and a two-stage adaptive testing methodology. In the eighth grade, a two-stage adaptive paper-and-pencil assessment was administered in small groups. At kindergarten and first grade, the assessment included three cognitive domains—reading, mathematics, and general knowledge. General knowledge was replaced by science at the third, fifth, and eighth grades. Children's height and weight were measured at each data collection point, and a direct measure of children's psychomotor development was administered in the fall of the kindergarten year only. In addition to these measures, the ECLS-K collected information about children's social skills and academic achievement through teacher reports, and through student reports at the third, fifth, and eighth grades.
A computer-assisted telephone interview with the children's parents/guardians was conducted at each data collection point. Parents/guardians were asked to provide key information about the ECLS-K sample children on subjects such as family demographics (e.g., family members, age, relation to child, race/ethnicity), family structure (e.g., household members and composition), parent involvement, home educational activities (e.g., reading to the child), child health, parental education and employment status, and the social skills and behaviors of their children.
Data on the schools that children attended and their classrooms were collected through self-administered questionnaires completed by school administrators and classroom teachers. Administrators provided information about the school population, programs, and policies. At the classroom level, data were collected from the teachers on the composition of the classroom, teaching practices, curriculum, and teacher qualifications and experience. In addition, special education teachers and related services staff provided reports on the services received by children with disabilities.
New data are being collected on a 2011 ECLS-K cohort. The first data collection began during the fall and spring of the 2010-11 school year. Follow-ups are planned for 2011–12 and in the spring from 2013 to 2016. This study will be similar to the older ECLS-K cohort, but it will provide insight into the more recent education policy changes, such as the No Child Left Behind Act, the increase in school choice, and the increase in English language learners.
Further information on the ECLS-K may be obtained from
Early Childhood, International, and Crosscutting Studies Division
Early Childhood and Household Studies Program
National Center for Education Statistics
1990 K Street NW
Washington, DC 20006