Survey Results

Survey Items: Survey instrument item number for children 6-11 years: C4,5; for children 12-17 years: C5,6
Variable name in public use data file: BMICLASS

Denominator: Children age 10-17 years

Numerator: Adolescents, age 10-17 years, who are overweight or obese

Revisions and Changes: There were changes to the wording of this question. For more information about the changes, click here.
Due to changes in the survey’s mode of data collection and sampling frame, as well as adjustments to item wording where necessary, MCHB alerts data users that it is not be possible to compare estimates from the redesigned survey to those from previous iterations of the NSCH or NS-CSHCN or to conduct related trend analyses. The redesigned NSCH will support trend analyses beginning with data from 2016.

Additional Notes: Assessment of body fat in children and teenagers is approached differently than for adults. Because growth patterns differ, BMI in youth is age and gender specific. BMI-for-age categories are: Underweight - Less than the 5th percentile; Healthy weight - 5th percentile to less than the 85th percentile; Overweight - 85th to less than the 95th percentile; Obese - Equal to or greater than the 95th percentile. Additional information about BMI-for-age is available from the CDC website. The child's age in months was used to calculate BMI-for-age. However, since the NSCH reports age only in years, all children were assumed to be at the midpoint of their age-year for this calculation. BMI for children under 10 years of age was not reported in this measure. In the NSCH, BMI-for-age is based on parents' recollection of the selected child's height and weight. Responses to questions ask about child's current height and weight were not independently verified (e.g., measurement, health records, etc.). A study comparing parent-reported height and weight estimates from the 2003 NSCH with results of physical measurement from the National Health and Nutrition Examination Survey (NHANES) revealed that parents typically overestimate height and underestimate weight of children younger than 10 years of age. (Lara J. Akinbami, Cynthia L. Ogden. (2009) Childhood Overweight Prevalence in the United States: The Impact of Parent-reported Height and Weight. Obesity 17:1574-1580)

Treatment of Unknown Values: Missing values due to non-response or a “don’t know” response are not included in the denominator when calculating prevalence estimates and weighted population counts displayed in the data query results table. In the majority of cases, the proportion of missing values is less than 2%. Exceptions are noted in the form of a Data Alert at the bottom of a results table. The exclusion of these values does not change the prevalence estimates (%) and only marginally affects the weighted population counts (Pop. Est.). If missing cases are handled in any other way, details can be found in the "Additional notes" section above.

History and Development:
Overview of the Title V Block Grant: The Title V Maternal and Child Health (MCH) Services Block Grant Program is a federal-state partnership in 59 states and jurisdictions to improve the health and well-being of MCH populations through the development of public health systems of care which are family-centered, community-based and culturally appropriate. To improve accountability and demonstrate the impact of the Title V Block Grant Program, significant revisions were implemented with the 2015 application and annual report guidance, which included changes to National Performance Measures (NPM) and National Outcome Measures (NOM). More information about the block grant can be obtained at the MCHB website.
About NSCH: The Maternal and Child Health Bureau (MCHB) funds and directs the National Survey of Children’s Health (NSCH), and develops survey content in collaboration with the U.S. Census Bureau and a Technical Expert Panel. The Technical Expert Panel consists of experts in survey methodology and children’s health, federal and state stakeholders, clinicians and researchers. The U.S. Census Bureau conducts the survey, oversees the sampling, and produces a final data set of survey results. Respondents’ cognitive understanding of the survey questions was assessed during the pretest phase and revisions were made. Previously validated questions and scales are used when available.
Prior to 2016, the NSCH and the National Survey of Children with Special Health Care Needs were each conducted three times as interviewer-assisted telephone surveys using random digit dial sampling. In 2016, the two surveys were combined into a single self-administered questionnaire. Due to decline in the number of households with landline telephones, the NSCH now utilizes an address-based sampling method to select participating households, thus all invitations are sent by mail. Participants may choose to complete the survey either online using a secure website or a mailed paper version of the survey. All final data components are verified by the Census Bureau, MCHB and DRC/CAHMI staff prior to public release. More information can be found in the “Review the Surveys” section of this website.