Component Description
The Food Security section (variable name prefix FSQ) provides individual and household-level interview data on the following topics:
1. Household food security
In the household interview, an adult responded to the
U.S. Food Security Survey Module (US FSSM) questions (Bickel G, et. al, 2000).
All households were asked 10 questions. These questions refer to all household
members, not just NHANES participants. One categorical household-level variable
was created to characterize the food security status for adults in the
household. The categorical variable derived from these responses is released on
each household participant’s record. Different from previous NHANES cycles, the
8 US FSSM items that were unique to households with children were not included
in NHANES August 2021-August 2023 to reduce survey participant burden. Please
refer to the Analytic Notes section for additional details.
A question on individual household members use of emergency foods from food banks, soup kitchens, or other organizations in the last 12 months is also included in this section.
2. Supplemental Nutrition Assistance Program (SNAP)/Food Stamp program benefits
All SNAP/Food Stamp benefits questions were collected at the household level. To obtain a more complete picture of all benefit recipients in the household, the data collection instruments were designed to identify each household member’s SNAP/Food Stamp benefit receipt status using a household roster. The data were then summarized at the household level.
Within each household, for each family that participated in NHANES, one adult responded to questions about SNAP/Food Stamp benefits received by all household members. Information collected included whether anyone in the household had ever received SNAP/Food Stamp benefits; whether anyone in the household received benefits in the last 12 months; and whether anyone in the household is a current SNAP/Food Stamp benefits recipient. For households with benefit recipients in the past 12 months, the number of months benefits were received; the time since benefits were last received; and the amount of benefits the household received last was also collected.
Household-level data on SNAP/Food Stamp benefits are released on all household participants’ records. The time since benefits were last received and the time until anticipated benefits will be received was calculated for each family within the household, based on the family interview date, and released at the family level.
3. Women, Infants and Children (WIC) program benefits
Data collected for WIC benefits included three household-level questions as well as six individual-level questions for participants aged birth to 5 years, and one individual-level question for participants 1-5 years.
In the household interview, an adult from each family responded to the question on whether anyone in the household received WIC benefits in the last 12 months, followed by questions on current WIC participation in the last 30 days and the number of people in the household receiving WIC benefits. These household-level questions are released on all household participants’ records.
For participants aged birth to five years, information was collected on whether they ever received WIC benefits, current participation, total length (in months) of benefits received, and WIC participation during various important periods in early childhood, including prenatal, infancy, and 1-4 years old, and released on the individual participant’s record.
The table in Appendix 1 provides detailed information on each of the four FSQ components described above. Appendix 2 highlights the changes in the FSQ section among the latest three release cycles.
Quality Assurance & Quality Control
The automated interview systems used in NHANES are programmed with built-in consistency checks to reduce data entry errors. All the data were reviewed for accuracy and completeness. NHANES staff reviewed audio recordings of interviews, traveled to field sites to observe interviews, read interviewer comments, and attended training and re-training sessions to maintain the high-quality data.
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.
FSDAD (Adult food security category)
Ten FSSM questions were asked of households irrespective of if they had children. One categorical variable with four response levels was created based on the number of affirmative responses for those questions. This categorical variable could be used to characterize the overall food security status for the adults in the household. The algorithm used to derive the categorical variable is described below:
Count affirmative responses in these 10 items: FSD032a, FSD032b, FSD032c, FSD041, FSD052, FSD061, FSD071, FSD081, FSD092, and FSD102. Derive the codes as the following:
1 = Adult full food security: no affirmative response in any of these items.
2 = Adult marginal food security: 1-2 affirmative responses.
3 = Adult low food security: 3-5 affirmative responses.
4 = Adult very low food security: 6-10 affirmative responses.
No food security category is assigned if all or most of these items were answered as “don’t know” or “refusal.” There are 25 such records in the August 2021-August 2023 dataset. These records contain missing values for FSDAD.
FSD165-FSD235 (all variables for SNAP/Food Stamp benefits)
Information on the receipt of SNAP/Food Stamp benefits by all household members was provided in the present file: ever (FSQ165); the number of people ever received (FSD165N); received in the last 12 months (FSQ012); the number of people who received in the last 12 months (FSD012N); currently receiving (FSD230); the number of people currently receiving (FSD230N); number of months received benefits (FSD795); time since last received benefits (FSD225); and amount of benefits last received (FSD235). Receipt of SNAP/Food Stamp benefits by all individuals residing in the household, both survey and non-survey participants, was included. In households with more than one family where there were inconsistencies across families, all data were reviewed and reconciled.
FSD225 (Time since last received SNAP/Food Stamp benefits)
During the household interview, the respondent was asked to report the date that the household last received SNAP/Food Stamp benefits. A variable was then derived by calculating the number of days between the time the household last received the SNAP/Food Stamp benefit and the date of interview for the corresponding family. The derived variable was released as FSD225 at the family level.
FSQ235 (Amount last received SNAP/Food Stamp benefits)
The amount last received in benefits was determined by asking about the date and the amount last received by all persons in the household who received SNAP/Food Stamps in the last 12 months. The latest amount received by the household was released at the household level.
FSD795 (number of months received SNAP/Food Stamp benefits)
The number of months SNAP/Food Stamp benefits were received is included for households with current recipients and those who received them in the last 12 months. When a household had both current recipients and past recipients in the last 12 months, the total number of months were calculated by checking for overlapping months. For example, if a household member is currently receiving benefits from May to July, and another household member received benefits from February to May, the total number of months was 6 (2 + 4 = 6), in the past 12 months.
FSD760N (number of people in the household received WIC benefits in the past 30 days)
The family respondent was asked whether anyone living in the household received WIC benefits in the past 30 days. Respondents with affirmative answers were followed up with a question (i.e., FSQ770) asking them to identify all persons living in the household who received benefits from a household roster. In addition to these household-level questions, child participants were also asked about whether they were receiving WIC benefits at the time of their own interviews (i.e., FSD660ZC). Responses to FSQ770 and FSD660ZC were used to derive the data in FSD760N. Receipt of WIC benefits by both survey and non-survey participants residing in the household was included. In households with more than one family where there were inconsistencies across families, all data were reviewed and reconciled.
FSD670ZC (number of months the participant received WIC benefits)
This information was collected using two-part (number and unit) questions to allow respondents to report the length in either months or years. The released variable was edited to standardize the reported length to number of months.
Analytic Notes
NHANES has assessed household food security with the U.S. Food Security Survey Module (US FSSM) since 1999. In the August 2021-August 2023 cycle, the 8 items of the US FSMM that were unique to households with children were dropped to reduce survey participant burden. As result, the derived variable encoding household food security categories utilizing the full 18 US FSSM items (i.e., FSDHH) is not included in the present dataset. The adult food security category indicator (FSDAD) is still reported for all participants in the present dataset. FSDAD was derived from the 10 basic US FSSM items, including questions on overall household experiences associated with difficulty in meeting food needs, and specific questions on related behaviors among adult household members. Users should be cautious when comparing data from NHANES August 2021-August 2023 with previous survey cycles, and with reports using separate food security category indicators for households with and without children, such as the Household Food Security in the United States in 2023 (Rabbitt MP, et. al, 2024). For more information on food security measurement, please refer to the USDA's website at: Food Security in the U.S. - Measurement / Economic Research Service.
In the August 2021-August 2023 cycle, detailed individual-level WIC participation questions for women aged 12 years and over were dropped to reduce survey participant burden. However, their participation in the last 12 months and last 30 days would be included in the household level WIC participation items (i.e., FSD162, FSQ760, and FSD760N).
The NHANES household interview included two questionnaires: a sample participant questionnaire to collect information regarding each individual survey participant’s personal health status, and a family questionnaire to collect information at the family level, such as total income for the family, food availability in the family, etc. The sample participant questionnaire was answered by participants themselves (adult proxy for child under 16 years old). The family questionnaire required an adult family member, preferably the head of the family, to respond to these questions for the entire family. The information on household food security status and SNAP/Food Stamp program as well as WIC program benefits in the FSQ section were collected as part of this family questionnaire. In August 2021-August 2023, 1,325 participants had missing values for all of these items in the FSQ section because the family questionnaire was not administered. Most common reasons for missing the family questionnaire interview were: “no eligible adult respondent in the family available” or “refusal.”
FSQ data were collected as part of the household interview. Thus, the interview sample weights should be used in their analysis. However, if the data analysis requires merging of these data with data collected in the MEC, examination sample weights should be used for 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. Both are available on the NHANES website.