. 2021 Dec;111(12):2149–2156. doi: 10.2105/AJPH.2021.306517

TABLE 1—

Selected Sample Design Parameters: United States, National Health and Nutrition Examination Survey, 2015–2018 and 2021–2022

Characteristic	2015–2018⁸	2021–2022
Age of noninstitutionalized civilian target population	All ages	All ages
Geographic area	United States^a	United States^a
Sample design	4-y, stratified, clustered 4-stage samples	2-y, stratified, clustered 4-stage samples
Number of study locations	60	30
Domains for oversampling	Predesignated: 87 domains of gender–age groups for non-Hispanic Black persons; non-Hispanic, non-Black Asian persons; and Hispanic persons, and income–gender–age groups for other persons	Predesignated: 3 domains of age groups (0-19, 20-59, ≥ 60 y)
Oversampled: Hispanic persons; non-Hispanic Black persons; non-Hispanic, non-Black Asian persons; low-income White and other persons (at or below 185% of federal poverty level); children aged 0–11 y; and adults aged ≥ 80 y	Oversampled: younger (0–19 y) and older (≥ 60 y) age groups
Number of examined persons	18 248	10 000 (targeted)

^aIncludes 50 states and the District of Columbia. US territories are not included in the National Health and Nutrition Examination Survey sample.