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

Published: Mar 20, 2014

Principal Investigator(s):
United States Department of Education. Institute of Education Sciences. National Center for Education Statistics



Version V1

ECLS-K K-8 Full Sample Data

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.

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. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2014-03-20. https://doi.org/10.3886/ICPSR28023.v1

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1998 -- 2007

1998 -- 1999 (Fall-Kindergarten and Spring-Kindergarten)

1999 -- 2000 (Fall-First grade and Spring-First grade)

2001 -- 2002 (Spring-Third grade)

2003 -- 2004 (Spring-Fifth grade)

2006 -- 2007 (Spring-Eighth grade)

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.

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.

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.

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.

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.

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 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.

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




school administrator

survey data

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.

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.



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.

2011-05-27 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.


  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

  • The citation of this study may have changed due to the new version control system that has been implemented.