At A Glance

Noteworthy Characteristics

  • Includes measures of sleep.
  • Measures children’s height and weight.
  • Provides data on food security in the home.
  • Includes measures of physical activity in and outside of school.
  • Includes reports of children’s health and disability.



To collect data on children’s early school experiences in the United States (U.S.), beginning with kindergarten and following children through fifth grade. The ECLS-K:2011 provide information on children’s status at entry to school, their transition into school, and their progression through the elementary grades.

Target Population

The U.S. kindergarten class of 2010-11 as they progressed through the 2015-16 school year (when most children were in fifth grade).


Began in 2010. Conducted periodically. Information collected in the fall and the spring of kindergarten (2010-2011), the fall and spring of 1st grade (2011-2012), the fall and spring of 2nd grade (2012-2013), the spring of 3rd grade (2014), the spring of 4th grade (2015), and the spring of 5th grade (2016).


National Center for Education Statistics, U.S. Department of Education. Learn more about the federal agencies that collaborated with NCES on the ECLS-K:2011.

Special Note(s)

The Early Childhood Longitudinal Study (ECLS) program includes three longitudinal surveys that examine child development, school readiness, and early school experiences. In addition to the ECLS-K:2011, the ECLS program includes the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) and the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K).

The ECLS-K:2011 base year data also generalize to the population of schools with kindergarten programs in 2010-11.

The Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 data were collected two times a year when the children were in kindergarten (2010-11), first grade (2011-12), and second grade (2012-13). Although the fall kindergarten collection included the full ECLS-K:2011 sample, the fall collections for first and second grade were conducted with approximately one-third of the sample of children who participated in the base-year data collection. Spring data collections with the entire sample of children who participated in the base-year data collection were conducted for the children’s third-grade (2014), fourth-grade (2015), and fifth-grade (2016) school years.

The longitudinal nature of the ECLS-K:2011 data enables researchers to study how a wide range of family, school, community, and individual factors are associated with school performance.

System Contact:
Gail Mulligan, Project Officer
National Center for Education Statistics
Phone: +1 (202) 245-8413


Sample Design

Longitudinal, multistage probability sample design to obtain a nationally representative sample of children in kindergarten in the United States in 2010-11. Asians, Native Hawaiians, and other Pacific Islanders were oversampled. To learn more about the ECLS-K:2011 sampling design, see the ECLS-K:2011 user’s manuals available online at and

Sample Size

Approximately 20,230 children were sampled from 1,320 schools in the 2010-11 school year. On average, 23 kindergartners were sampled from each ECLS-K:2011 school. In some smaller schools, the entire population of kindergarten children was selected.

Special Note(s)

The ECLS-K:2011 data file is provided as a child-level data file containing one record for each child participating in the kindergarten-year data collection. However, the ECLS-K:2011 base- year data do generalize to the population of schools educating kindergartners or kindergarten-age children; an analyst interested in a school-level analysis can create a school-level file using the school ID provided in the data file.

The ECLS-K:2011 used a three-stage sample selection process:
• Stage 1: Primary sampling units (PSUs), which were geographic areas consisting of counties or groups of counties.
• Stage 2: Schools within sampled PSUs.
• Stage 3: Children within schools.

Key Variables


NameMethods of Assessment
Child’s birth weightInterview/questionnaire (parent/caregiver)
Child’s date of birthInterview/questionnaire (parent/caregiver)
Child’s race/ethnicityInterview/questionnaire (parent/caregiver)
Child’s sexInterview/questionnaire (parent/caregiver)
Household incomeInterview/questionnaire (parent/caregiver)
Disability (cognitive; equipment use; general; hearing; movement/physical; vision)Interview/questionnaire


NameMethods of Assessment
Family (child and adult) food security statusInterview/questionnaire (parent/caregiver)
Participation in national school meal programsInterview/questionnaire (parent/caregiver)
Participation in nutrition assistance programsInterview/questionnaire (parent/caregiver)
Percent students in school eligible for free and reduced-price lunchesInterview/questionnaire (school administrator)
Whether family eats breakfast and dinner togetherInterview/questionnaire (parent/caregiver)

Physical Activity-Related

NameMethods of Assessment
Frequency of physical activity each weekInterview/questionnaire (parent/caregiver)
Extracurricular activitiesInterview/questionnaire (parent/caregiver)
Hours spent in sedentary activity (i.e., television viewing, non-school reading, video games, Internet)Interview/questionnaire (parent/caregiver/before- and after-school care providers)
Frequency of recess in schoolInterview/questionnaire (teacher)


NameMethods of Assessment
Sleep disturbances and quality: Subjective satisfactionInterview/Questionnaire with Parent
Sleep duration and quantity: Total sleep time during workdays/schooldaysInterview/Questionnaire with Parent


NameMethods of Assessment
Height and weightMeasured


NameMethods of Assessment
Zip code, county and state of child’s household, National Center for Education Statistics school identifier, school’s zip code, county, and stateObtained from sampling frame and field staff records


NameMethods of Assessment
Child health care, visits to doctors and dentists, diagnosesInterview/questionnaire (parent/caregiver)
Parental depressionInterview/questionnaire (parent/caregiver)
Percent minority students in schoolInterview/questionnaire (school administrator)

Data Access and Cost

Data Availability

Currently public-use files for the Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011) kindergarten and first-grade rounds are available online. Restricted-use files are available for the kindergarten, first-grade, and second-grade rounds of the ECLS-K:2011. For information on the tentative data release dates for forthcoming ECLS-K:2011 data files, please see


Free of charge.

Special Note(s)

Both restricted-use and public-use data files are available. Learn more about the difference between restricted-use and public-use data files. A restricted data license must be obtained before users can access the DVD containing restricted-use files. Learn more about how to obtain a restricted data license.


Geocode Variable(s)

Census tract and zip codes for ECLS-K:2011 children's homes and schools are available on restricted-use data files. Schools’ Federal Information Processing Standard (FIPS) codes (both state and county) are also be available.

The restricted-use files have a variable FxFIPSST that indicates the state's FIPS code (the "x" refers to the round number). Learn more about matching these codes to the states' names.

Existing Linkages

Additional information on children’s schools is available by linking to school data from the National Center for Educational Statistics Common Core of Data (NCES/CCD) and Private School Universe Survey/Private School Survey Series (PSS) universe files, which pertain to U.S. public and private schools, respectively.

Special Note(s)

An IES Restricted-Use Data License is required to obtain geocode variables.

Although the restricted data do identify children’s state of residence, the ECLS-K:2011 sample was not designed to support state-level (or city- or county-level) estimates, as the sample is not representative of children in particular states (or cities or counties).

Selected Publications

For a list of publications using ECLS-K:2011 data, visit ECLS Publications and Products and ECLS Bibliography.


Mulligan, G.M., Hastedt, S., and McCarroll, J.C. (2012). First-Time Kindergartners in 2010-11: First Findings From the Kindergarten Rounds of the Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011). (NCES 2012-049). Washington, DC: National Center for Education Statistics.

Mulligan, G.M., McCarroll, J.C., Flanagan, K.D., and Potter, D. (2014). Findings From the First-Grade Rounds of the Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS- K:2011) (NCES 2015–109). Washington, DC: National Center for Education Statistics.

Mulligan, G.M., McCarroll, J.C., Flanagan, K.D., and Potter, D. (2015). Findings From the Second-Grade Rounds of the Early Childhood Longitudinal Study, Kindergarten Class of 2010–11 (ECLS-K:2011) (NCES 2015–077). U.S. Department of Education, Washington, DC: National Center for Education Statistics. Retrieved [June 2015] from



ECLS-K:2011 Kindergarten User's Manual, Public Version

ECLS-K:2011 Kindergarten-First Grade User's Manual, Public Version

ECLS-K:2011 Kindergarten-Second Grade User's Manual, Public Version


Before conducting any analyses, users are encouraged to review the ECLS-K:2011 study instrumentation to fully understand the study’s content, the flow of the items in the questionnaires/interviews, the group of respondents who answered specific questions, and the context in which the questions were asked.

The ECLS-K:2011 direct child assessment batteries are not publicly available due to copyright restrictions. However, the ECLS-K:2011 does have a website where an overview of the child assessments can be found.