Surveillance Systems

A surveillance system is a series of surveys conducted again and again to monitor long-term trends in public health. Several surveys are used to examine Americans’ weight status and factors that influence it. These surveys are conducted across several years to compare health among groups of people, and determine whether something is improving or worsening for specific groups.

Nutrition, Physical Activity, and Obesity

  • National Health and Nutrition Examination Survey (NHANES)
    NHANES is a continuous program designed to assess the health and nutritional status of adults and children in the United States. The annual survey consists of about 5,000 in-person interviews and standardized physical examinations. CDC uses NHANES data to report national estimates. NHANES should not be compared with other surveillance systems because their methods for data collection are different.
  • Behavioral Risk Factor Surveillance System (BRFSS)
    BRFSS is an on-going, state-based, telephone interview survey conducted by CDC and state health departments. It collects self-reported information on health conditions and risk behaviors among adults in all 50 states and select territories. CDC uses BRFSS data for state-level estimates. BRFSS should not be compared with other surveillance systems because their methods for data collection are different.
    Computer monitor displaying charts
  • Youth Risk Behavior Surveillance System (YRBS)
    YRBSS measures the prevalence obesity and monitors six behaviors that contribute to the leading causes of death and disability among youth and young adults, including unhealthy dietary behaviors and physical inactivity.
  • National Health Interview Survey (NHIS)
    The NHIS has monitored the health of the nation since 1957. NHIS data are collected through personal household interviews.
  • CDC uses data from the Special Supplemental Nutrition Program for Women, Infants, and Children  Participants and Program Characteristics (WIC PC) for weight status surveillance among young children in families with lower incomes. Data is available for children aged 2 to 4 years and infants aged 3 to 23 months.  The WIC PC data is included in the DNPAO’s Data, Trends, and Maps.
  • National Collaborative on Childhood Obesity Research (NCCOR) Catalogue of Surveillance Systems
    The catalogue provides one-stop access to over 100 publicly available datasets relevant to childhood obesity research.


  • School Health Policies and Programs Study
    The School Health Policies and Programs Study is a national survey periodically conducted to assess school health policies and practices at the state, district, school, and classroom levels. This includes nutrition services, education, and policies.
  • School Health Profiles
    The School Health Profiles is a system of surveys assessing school health policies and practices in states, large urban school districts and territories. This includes school health education requirements, nutrition and dietary behavior topics and school health policies and practices related to nutrition and other topics.

Physical Activity

  • Physical Activity Surveys
    Several national surveys track physical activity in many age groups and at different levels for US public health objectives. See background information for each and understand how physical activity is assessed.


  • National Immunization Survey (NIS)
    NIS provides national, state, and selected urban-area estimates of vaccination coverage rates for US children ages 19 to 35 months. Since July 2001, breastfeeding questions have been included to assess the population’s breastfeeding practices.
  • Infant Feeding Practices Survey II
    CDC collaborates with researchers from the Food and Drug Administration to conduct this nationwide longitudinal study focused on infant feeding practices and the diets of women from their third trimester to 12 months postpartum.
  • Maternity Practices in Infant Nutrition and Care (mPINC)
    This survey of US labor and delivery service facilities is an effort to monitor maternity care practices associated with successful breastfeeding promotion and support. The survey occurs every other year; the first survey was in 2007.
  • SummerStyles
    SummerStyles is a private proprietary national marketing survey that annually collects health-related opinions of men and women aged 18 years and older. Formerly called HealthStyles, the survey includes a large, demographically diverse sample of the US population and reflects current social and cultural norms. CDC has contributed breastfeeding questions to the survey since 1999.
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