Early Childhood Longitudinal Study [United States]: Kindergarten Class of 1998-1999, Kindergarten-Eighth Grade Full Sample (ICPSR 28023)

Alternate Title:  ECLS-K K-8 Full Sample Data

Principal Investigator(s):


The Early Childhood Longitudinal Study Kindergarten Class of 1998-1999, Kindergarten-Eighth Grade Full Sample includes the kindergarten, first, third, fifth, and eighth grade data collections for the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K). Unlike the public-use longitudinal files released in previous rounds, this file contains all data for all ECLS-K sample cases that have been publicly released in any of the rounds. Thus, it can be used for within-year (cross-sectional) analyses of any round of data collection and cross-year (longitudinal) analyses of combinations of rounds. It focuses on children's early school experiences beginning with kindergarten through eighth grade. It is a nationally representative sample that collects information from children, their families, their teachers, and their schools. ECLS-K provides data about the effects of a wide range of family, school, community, and individual variables on children's cognitive, social, emotional, and physical development, their early learning and early performance in school, as well as their home environment, home educational practices, school environment, classroom environment, classroom curriculum, and teacher qualifications. The list below summarizes each wave of this study.

  • 1998-1999 (the Kindergarten year-Rounds 1 and 2): The ECLS-K child assessments, parent interviews, and teacher questionnaires were conducted in the fall. Children, parents, and teachers participated again in the spring, along with school administrators.

  • 1999-2000 (the First grade year-Rounds 3 and 4): The ECLS-K conducted child assessments and parent interviews for a 30 percent sub-sample in the fall. The full sample of children, parents, teachers, and school administrators participated in the spring.

  • 2002 (the Third grade year-Round 5): The ECLS-K conducted child assessments and parent interviews in the spring. Teachers and school administrators completed questionnaires.

  • 2004 (the Fifth grade year-Round 6): The ECLS-K conducted child assessments and parent interviews in the spring. Teachers and school administrators completed questionnaires.

  • 2007 (the Eighth grade year-Round 7): The ECLS-K followed the children into middle school. Information was collected from the children, their parents, teachers, and school administrators.

For more detailed information about this data collection, please refer to the user guide.

Series: Early Childhood Longitudinal Study (ECLS) Series

Access Notes

  • These data are freely available.


WARNING: This study is over 150MB in size and may take several minutes to download on a typical internet connection.

DS2:  ECLS-K Base Year School-Level File - Download All Files (16.1 MB)
DS3:  ECLS-K Base Year Teacher-Level File - Download All Files (59.5 MB)
DS4:  ECLS-K Correct Theta Scores for the Kindergarten-Eighth Grade Full Sample Data Errata File - Download All Files (19.1 MB)
DS5:  ECLS-K Round 5 Base Weights and Adjustment Factors - Download All Files (107 MB)
DS6:  ECLS-K Cross-Round through Round 5 Weight Status - Download All Files (8.5 MB)
DS7:  ECLS-K Round 6 Base Weights and Adjustment Factors - Download All Files (120.7 MB)
DS8:  ECLS-K Cross-Round through Round 6 Weight Status - Download All Files (8.9 MB)
DS9:  ECLS-K Round 7 Base Weights and Adjustment Factors - Download All Files (122.1 MB)
DS10:  ECLS-K Cross-Round through Round 7 Weight Status - Download All Files (9.4 MB)

Study Description


United States Department of Education. Institute of Education Sciences. National Center for Education Statistics. Early Childhood Longitudinal Study [United States]: Kindergarten Class of 1998-1999, Kindergarten-Eighth Grade Full Sample. ICPSR28023-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2011-05-27. http://doi.org/10.3886/ICPSR28023.v1

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Scope of Study

Subject Terms:   birth, child care, child development, classroom environment, disabilities, early childhood education, elementary education, emotional development, family life, home environment, infants, language, mathematics, minorities, reading skills, school age children, school readiness, schools, science education, teacher evaluation

Geographic Coverage:   United States

Time Period:  

  • 1998--2007

Date of Collection:  

  • 1998--1999
  • 1999--2000
  • 2001--2002
  • 2003--2004
  • 2006--2007

Unit of Observation:   children, parent, teacher, school administrator

Universe:   Children and their families, teachers, and schools in the United States.

Data Types:   survey data

Data Collection Notes:

There is an errata sheet and data file that pertain to errors in theta scores released in August 2009 for the kindergarten through fifth grade theta scores on the public-use longitudinal dataset. The eighth grade scores are included as well to provide users with the complete set of ECLS-K theta scores in one file. Specifically, the data released with this errata correct for errors in the theta scores released through the Early Childhood Longitudinal Study [United States]: Kindergarten Class of 1998-1999, Kindergarten-Eighth Grade Full Sample Public-Use Data File.

The main data file, Kindergarten-Eighth Grade Full Sample Public-Use Data File, is organized on the Child-Level. For the base year, data is available on the School-Level and Teacher-Level.

Every document used in any wave throughout the entire study is available for download. This includes questionnaires, record layouts, errata sheets, user guides, etc. These documents have been organized by type and wave. For more information on locating particular documents, please refer to the ECLS-K document matrix.

The Stata files provided for the K-8 full sample data are those taken directly from the National Center for Education Statistics (without any modifications). Due to the large size of the data files, Stata needs to be installed with the maximum memory alloted from the operating system.

Given the size of the K-8 file, it may take several minutes to get the data and ready-to-go files to load.

The National Center for Education Statistics (NCES) releases the ECLS-K data as public-use and restricted-use files; ICPSR only releases the public-use files. Restricted-use files differ from the public-use version in that they contain variables that have been suppressed in the K-8 public-use version to protect respondent confidentiality (such as geographic indicators). Nonetheless, suppressed variables are labeled on the K-8 public-use file to maintain structure; data values are simply set to a reserve code or blanked. Other modifications found in the K-8 public-use file include composite variables describing children's family structure and family member characteristics. See Table 7-16 of the User Guide for a list of variables that are modified or suppressed in the K-8 public-use version of the data. If those data are of particular value to the analyst, the user can apply on-line for a restricted-use data license at http://nces.ed.gov/pubsearch/licenses.asp.



The ECLS-K employed a multistage probability sample design to select a nationally representative sample of children attending kindergarten in 1998-1999. In the base year, the primary sampling units (PSUs) were geographic areas consisting of counties or groups of counties. The second-stage units were schools within sampled PSUs. The third- and final-stage units were students within schools.

The sample design for eighth grade called for including all 12,129 children eligible after fifth grade (regardless of their fifth-grade response status), and following all movers without any subsampling. In the ECLS-K first-grade to fifth-grade data collections, subsampling of movers was used to reduce data collection costs. The initial sample size was developed taking into account the reduction in sample size and increase in the variability of the weights of the respondents resulting from the subsampling. As the design was extended beyond fifth grade (the initial planning of the ECLS-K did not plan for this extension into eighth grade), a change in the methods of handling movers to avoid subsampling them was needed to achieve the major analytic goals. The vast majority of children were not in the same school from kindergarten to eighth grade (having moved out of elementary schools into middle schools), and subsampling these movers would result in substantial losses in sample size and precision of the estimates for the eighth grade.

Mode of Data Collection:   computer-assisted personal interview (CAPI), computer-assisted telephone interview (CATI), mail questionnaire, self-enumerated questionnaire, on-site questionnaire

Response Rates:   The ECLS-K overall response rate can be computed by the product of the school-level response rate from the base year and the completion rates from each round of data collection after the base year. The instrument-specific overall response rates are driven by the school-level response rate in the base year. Since the overall school response rate is low at 74 percent, overall response rates for all instruments cannot be higher than 74 percent.

Presence of Common Scales:  

Many scales were used throughout the study. Categorically, they are as follows:

  • Child Assessments and Questionnaires

  • Parent Interviews

  • General Education Teacher Questionnaires

  • Special Education Teacher Questionnaires

  • School Administrator Questionnaires

For more information, please refer to Chapter 2 of the user guide for the appropriate year.

Extent of Processing:  ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:

  • Standardized missing values.
  • Checked for undocumented or out-of-range codes.


Original ICPSR Release:  

Version History:

  • 2014-03-20 Added a Study Overview document.
  • 2013-08-08 The ECLS-K instrument matrix has been created.
  • 2013-02-28 A user guide containing a brief summary of all data and documentation files available for this study has been added.

Resources Related To This Study

The impact of child-care subsidies on child development: Evidence from geographic variation in the distance to social service agencies Reports & Papers
Kids today: Changes in school-readiness in an early childhood era Reports & Papers
Do the effects of early childhood interventions systematically fade?: Exploring variation in the persistence of preschool effects Reports & Papers
Patterns of early reading and social skills associated with academic success in elementary school Reports & Papers
Child care subsidies, maternal health, and child-parent interactions: Evidence from three nationally representative datasets Reports & Papers

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Research Connections is supported by grant #90YE0104 from the Office of Planning, Research and Evaluation, Administration for Children and Families, U.S. Department of Health and Human Services. The contents are solely the responsibility of the National Center for Children in Poverty and the Inter-university Consortium for Political and Social Research and do not necessarily represent the official views of the Office of Planning, Research and Evaluation, the Administration for Children and Families, or the U.S. Department of Health and Human Services.

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