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Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)

1. Overview

Early Childhood Longitudinal Study, Birth Cohort (ECLS-B)
ECLS collects data from:
  • Children
  • Parents/guardians
  • Child care providers and preschool teachers
  • Kindergarten teachers

The Early Childhood Longitudinal Study (ECLS) program is one of the active longitudinal surveys sponsored by NCES. The ECLS program includes three cohorts: a birth cohort and two kindergarten cohorts (the kindergarten class of 1998–99 and the kindergarten class of 2010–11). The birth cohort study (ECLS–B) followed a sample of children born in 2001 from birth through kindergarten; the first kindergarten study (ECLS–K) followed a sample of children who were in kindergarten in the 1998–99 school year through the eighth grade; and the second kindergarten study (ECLS–K:2011) is following a sample of kindergartners in the 2010–11 school year through the fifth grade. The ECLS provides comprehensive and reliable datasets with information about the ways in which children are prepared for school and how children develop within their family, early childhood, and school environments.


The ECLS provides national data on (1) children’s status at birth and at various points thereafter; (2) children’s transitions to nonparental care, early education programs, and school; and (3) children’s experiences and growth through the eighth grade. These data enable researchers to test hypotheses about the associations and interactions of a wide range of family, school, community, and child characteristics with children’s development, early learning, and performance in school.


The ECLS has three cohort studies–two kindergarten cohort studies (ECLS–K and ECLS–K:2011) and a birth cohort study (ECLS–B)–and each of these has its own components. This chapter describes the birth cohort study, ECLS–B. For details on the first kindergarten cohort study, see the handbook chapter for ECLS–K. Details on the 2011 kindergarten cohort study can be found in the ECLS–K:2011 handbook chapter.

The Early Childhood Longitudinal Study, Birth Cohort. The ECLS–B, which began in October 2001, was designed to study children’s early learning and development from birth through the fall of the kindergarten year. Over the course of the study, data were collected from multiple sources, including birth certificates, children, parents/guardians, nonparental care providers, and teachers. Data from the Common Core of Data (CCD) and the Private School Survey (PSS) were linked to provide information for the schools where the children attended kindergarten. These components are described below.

Birth certificates. These records provided information on the date of birth, child’s sex, parents’ education, parents’ race and ethnicity (including Hispanic origin), mother’s marital status, mother’s pregnancy history, prenatal care, medical and other risk factors during the pregnancy, complications during labor and birth, and child’s health characteristics at birth (such as congenital anomalies, abnormal conditions of the baby, and the baby’s Apgar score).

Parent/guardian interviews. A parent/guardian interview was conducted in the children’s home at each data collection point to capture information about the children’s early health and development, their experiences with family members and other significant people in their lives, the parents/guardians as caregivers, the home environment, and the neighborhood in which they lived. In most cases, the parent/guardian interviewed was the child’s mother or female guardian.

Child assessments. Beginning at 9 months, children participated in activities designed to measure important developmental skills in the cognitive, socioemotional, and physical domains.

Cognitive domain. The cognitive assessments at the 9–month and 2–year data collections assessed general mental ability, including problem solving and language acquisition. The Bayley Short Form–Research Edition (BSF–R), designed specifically for the ECLS–B, was utilized in the 9–month and 2–year data collections and consists of selected items from the Bayley Scales of Infant Development (BSID–II).

The cognitive assessments at the preschool, kindergarten 2006, and kindergarten 2007 data collections assessed early reading and mathematics and consisted of items from the ECLS–K as well as other studies and instruments. Color knowledge also was assessed in the preschool data collection.

Socioemotional domain. The Nursing Child Assessment Teaching Scale (NCATS) was used in the 9–month collection to assess child–parent interactions. An attachment rating, the Toddler Attachment Sort–45 (TAS–45), was used in the second round of data collection. A videotaped parent–child interaction (the Two Bags Task) was also used in the second and third rounds of data collection.

Physical domain. In the 9–month data collection, children’s height, weight, and middle upper arm circumference were measured. Additionally, a measure of head circumference was taken for children born with very low birth weight. These physical measures were obtained again at all follow–up data collections. Additionally, children’s fine and gross motor skills were assessed at all data collections. At the 9–month and 2–year collections, motor skills were assessed using the BSF–R motor scale. At the preschool, kindergarten 2006, and kindergarten 2007 collections an assessment was specifically designed for the ECLS–B, in part using items adapted from the Early Screening Inventory–Revised (ESI–R) and the Bruininks–Oseretsky Test of Motor Proficiency (BOT).

Nonparental care and education providers. Individuals and organizations that provided regular care for a child were interviewed with the permission of the child’s parent/guardian. The care providers were asked about their backgrounds, teaching practices and experience, the children in their care, and children’s learning environments. This information was collected from the 2–year data collection on. In the kindergarten 2006 and 2007 collections, a wrap–around early care and education provider interview was used for those children who were in kindergarten and had a before– or after–school care arrangement.

Teacher questionnaires and school data. Once the children entered kindergarten, their classroom teachers provided information on their classrooms and on children’s cognitive and social development. Information for the school each child attended was obtained from NCES’s school universe data files–the Common Core of Data (CCD) for public schools and the Private School Universe Survey (PSS) for private schools.

Father questionnaires. Fathers (both resident and nonresident fathers) completed a self–administered questionnaire, which asked questions about the particular role fathers play in their children’s lives. The questionnaires collected information about children’s well–being, the activities fathers engage in with their children, and key information about fathers as caregivers. Both resident and nonresident father questionnaires were included in the collections when the children were 9 months old and 2 years old. The resident father questionnaire was included in the preschool collection. No father questionnaires were included in the kindergarten collections.




The ECLS–B collected data when the children were about 9 months old (2001–02), about 2 years old (2003), about 4 years old (the preschool collection, 2005), and in kindergarten (2006 and 2007). Note that because of age requirements for school entry, children sampled in the ECLS–B entered kindergarten in two different school years. All study children were included in the kindergarten 2006 collection, regardless of their enrollment status or grade in school. The kindergarten 2007 collection included just a portion of the total ECLS–B sample: children who were not yet in kindergarten in the 2006 collection, children who were in kindergarten in the 2006 collection and were repeating kindergarten in the 2007 collection, and twins of children in these groups. The ECLS–B study ended with the kindergarten 2007 round of collection.