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Kindergarten Class of 1998-99 (ECLS-K)

Study Information

The Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K) focuses on children's early school experiences beginning with kindergarten and following children through middle school. 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 children in ECLS-K came from both public and private schools and attended both full-day and part-day kindergarten programs. They came from diverse socioeconomic and racial/ethnic backgrounds. Also participating in the study were the children's parents, teachers, and schools.


Children, their families, their teachers, and their schools provided information on children's cognitive, social, emotional, and physical development. Information on children's home environment, home educational activities, school environment, classroom environment, classroom curriculum, and teacher qualifications also was collected.


The ECLS-K is a longitudinal study that followed the same children from kindergarten through the 8th grade. Information was collected in the fall and the spring of kindergarten (1998-99), the fall and spring of 1st grade (1999-2000), the spring of 3rd grade (2002), the spring of 5th grade (2004), and the spring of 8th grade (2007).



The ECLS-K collected information from a nationally representative sample of kindergartners, their parents, teachers, and schools all across the United States.


No large national study focused on education had followed a cohort of children from kindergarten entry to middle school until the ECLS-K. The ECLS-K was designed to provide comprehensive and reliable data that can be used to describe and to understand better children's development and experiences in the elementary and middle school grades, as well as how children’s early experiences relate to their later development, learning, and experiences in school. The multifaceted data collected across the years allow researchers and policymakers to study how various child, home, classroom, school, and community factors at various points in children’s lives relate to cognitive, social, emotional, and physical development.


Trained evaluators assessed children in their schools and collected information from parents over the telephone. Teachers and school administrators were contacted in their schools and asked to complete questionnaires.


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