Early, D. M., Iruka, I. U., Ritchie, S., Barbarin, O. A., Winn, D.-M. C., Crawford, G. M., . . . Pianta, R. C. (2010). How do pre-kindergarteners spend their time? Gender, ethnicity, and income as predictors of experiences in pre-kindergarten classrooms. Early Childhood Research Quarterly, 25(2), 177–193. doi:10.1016/j.ecresq.2009.10.003
Federal Interagency Forum on Child and Family Statistics. (2015). America’s children: Key national indicators of well-being, 2015. Washington, DC: Government Printing Office.
Jacobson Chernoff, J., Flanagan, K. D., McPhee, C., Consulting, M., & Park, J. Preschool: First findings from the preschool follow-up of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) (NCES 2008-025). Washington, DC: National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education.
National Center for Health Statistics. National Survey of Children's Health, 2011/12. from Child and Adolescent Health Measurement Initiative, Data Resource Center for Child and Adolescent Health.
OECD. (2012). Education at a glance 2012: OECD indicators. Paris, France: Organisation for Economic Cooperation and Development. doi:10.1787/eag-2012-en
Tandon, P. S., Zhou, C., & Christakis, D. A. (2012). Frequency of parent-supervised outdoor play of US preschool-aged children. JAMA Pediatrics, 166(8), 707–712. doi:10.1001/archpediatrics.2011.1835 Tandon, P. S., Zhou, C., Lozano, P., & Christakis, D. A. (2011). Preschoolers’ total daily screen time at home and by type of child care. The Journal of Pediatrics, 158(2), 297–300. doi:10.1016/j.jpeds.2010.08.005
U.S. Department of Education. Early Childhood Longitudinal Study: Kindergarten Class of 1998–99 (ECLS-K). Washington, DC: Institute of Education Sciences, National Center for Education Statistics.
Zill, N., & West, J. (2001). A portrait of American children when they begin school: Findings from the Condition of Education 2000 (NCES 2001–035). Washington, DC: U.S. Department of Education, National Center for Education Statistics.