title: National Health and Nutrition Examination Survey: National Youth Fitness Survey Estimation Procedures, 2012.
abstract: BACKGROUND
  The National Health and Nutrition Examination Survey's (NHANES) National Youth Fitness Survey (NNYFS) was conducted in 2012 by the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS). NNYFS collected data on physical activity and fitness levels to evaluate the health and fitness of children aged 3-15 in the United States. The survey comprised three levels of data collection: a household screening interview (or screener), an in-home personal interview, and a physical examination. The screener's primary objective was to determine whether any children in the household were eligible for the interview and examination. Eligibility was determined by preset selection probabilities for desired sex-age subdomains. After selection, the in-home personal interview collected demographic, health, physical activity, and nutrition information about the child as well as information about the household. The examination included physical measurements and fitness tests.
  
  
  OBJECTIVE
  This report provides background on the NNYFS program and summarizes the survey's sample design specifications. The report presents NNYFS estimation procedures, including the methods used to calculate survey weights for the full sample as well as a combined NHANES/NNYFS sample for 2012 (accessible only through the NCHS Research Data Center). The report also describes appropriate variance estimation methods. Documentation of the sample selection methods, survey content, data collection procedures, and methods to assess nonsampling errors are reported elsewhere.
authors.affiliation: National Center for Health Statistics.
authors.forename: Clifford L
authors.initials: CL
authors.lastname: Johnson
authors.affiliation: Westat.
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Dohrmann
authors.affiliation: Westat.
authors.forename: Van de
authors.initials: Vd
authors.lastname: Kerckove
authors.affiliation: Westat.
authors.forename: Mamadou S
authors.initials: MS
authors.lastname: Diallo
authors.affiliation: Westat.
authors.forename: Jason
authors.initials: J
authors.lastname: Clark
authors.affiliation: Westat.
authors.forename: Leyla K
authors.initials: LK
authors.lastname: Mohadjer
authors.affiliation: National Center for Health Statistics.
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Burt
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D015340:Epidemiologic Research Design; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006304:Health Status; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D009043:Motor Activity; D009309:National Center for Health Statistics, U.S.; D009749:Nutrition Surveys / Q000706:statistics & numerical data; D010808:Physical Examination; D010809:Physical Fitness; D012494:Sampling Studies; D014481:United States