• Component Description
• Eligible Sample
• Interview Setting and Mode of Administration
• Quality Assurance & Quality Control
• Data Processing and Editing
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • ECD070A - Weight at birth, pounds
  • ECD070B - Weight at birth, ounces
  • ECQ075 - CHECK ITEM
  • ECQ080 - Weight more/less than 5.5 lbs
  • ECQ090 - Weight more/less than 9.0 lbs
  • ECQ095 - CHECK ITEM
  • WHQ030E - How do you consider your child's weight
  • MCQ080E - Your child was overweight

National Health and Nutrition Examination Survey

August 2021-August 2023 Data Documentation, Codebook, and Frequencies

Early Childhood (ECQ_L)

Data File: ECQ_L.xpt

First Published: September 2024

Last Revised: NA

Component Description

The Early Childhood questionnaire (variable name prefix ECQ) section of the Sample Person Questionnaire provides personal interview data for children, including birth weight, and the proxy’s assessment of the participant’s weight.

Eligible Sample

Participants aged birth to 15 years in the NHANES August 2021-August 2023 sample are included in this dataset. However, the ages of participation for some questions in this section vary. Please review the codebook carefully. Frequency counts were verified during the preparation of the file.

Interview Setting and Mode of Administration

These questions were asked by trained interviewers using the Computer-Assisted Personal Interview (CAPI) system in the participant’s home or by telephone. 

For details on the administration of the ECQ_L, please refer to the 2022 Interviewer Procedures Manual – October 2022 (cdc.gov) and August 2021-August 2023 NHANES Early Childhood – ECQ Sample Person Participant Questionnaires on the NHANES website.

Quality Assurance & Quality Control

The CAPI system is programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire. All data was reviewed by the NHANES field office staff for accuracy and completeness.

Data Processing and Editing

Frequency counts were checked, "skip" patterns were verified, and the reasonableness of question responses was reviewed. Edits were made to some variables to ensure the completeness, consistency, and analytic usefulness of the data. Edits were also made, when necessary, to address data disclosure concerns. When a variable was modified globally, as part of the editing process, the third letter in the variable name was changed from a Q (i.e., ECQ) to a D (i.e., ECD). For example, some data were collected using two variables (a number variable and a unit of measure variable) but combined into a single variable for data release purposes.

For ECD070A (weight at birth, pounds) and ECD070B (weight at birth, ounces), all responses of 3 pounds or under were collapsed into a single category with ECD070A coded as “3” and ECD070B coded as “0.” Similarly, for ECD070A and ECD070B all responses of 11 pounds or over were collapsed into a single category, with ECD070A coded as “11” and ECD070B coded as “0.” This was done to protect the confidentiality of survey participants.

Analytic Notes

Although data in this file were collected as part of the household questionnaire, if they are merged with the MEC exam data, exam sample weights should be used for the analyses.

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

Codebook and Frequencies