Atkins-Burnett of the University of Michigan, and Nick Zill of Westat. Their comments and suggestions are appreciated, and the final report reflects many of their suggestions.We would also like to thank the 20,000 kindergarten children and their parents, and the more than 3,000 kindergarten teachers who participated during the base year of the study. We would like to thank the administrators of the schools we visited across the United States for allowing us to work with their children, teachers and parents, and for providing us with information about their schools. We are especially appreciative of the assistance we received from Chief State School Officers, district superintendents and staff, and private school officials.Westat, Incorporated-in affiliation with the Institute for Social Research and the School of Education at the University of Michigan, and the Educational Testing Service, under the direction of the National Center for Education Statistics (NCES)-conducted the base-year study. We would like to express our appreciation for the efforts of the staff from each of these organizations, and especially to the more than 400 field staff who conducted the child assessments and parent interviews in fall 1998 and spring 1999.We wish to acknowledge the support that we have received from the Head Start Bureau of the Administration on Children, Youth and Families; the Economic Research Service of the U.S. Department of Agriculture; the National Institute for Child Health and Human Development; and the U.S. Department of Education's Office of Special Education Programs, Office of Bilingual Education and Minority Languages Affairs, and Planning and Evaluation Service.We would like to thank Elvie Germino Hausken and Jonaki Bose of the National Center for Education Statistics, and Amy Rathbun, Jill Walston, Nikkita Taylor, and DeeAnn Brimhall of the Education Statistics Services Institute for their hard work and dedication in supporting all aspects of the ECLS-K program.A special thank you to Kendra Chandler Webb, age 9 (1994), for designing the ECLS logo, and to Westat for aiding in the design of the cover.v Executive SummaryThe kindergarten year marks a period of rapid change in the ways children think about themselves and the world around them (Bredekamp and Copple 1997;Sameroff and McDonough 1994). This change is influenced by both developmental factors (e.g., age, maturation) and environmental factors (e.g., schooling, home educational activities, family resources). Across this first year of schooling, children will acquire the knowledge and skills that will prove integral to their future success in school and in life.Children enter school demonstrating a vast array of knowledge and skills, some children further along than others (West, Denton, and Germino Hausken 2000). The kindergarten year serves multiple purposes and is geared toward the development of both cognitive and noncognitive knowledge and skills (Seefeldt 1990). And, depending on the child, knowledge and skills develop in different areas and at di...