Nonresponse in the National Survey of Children's Health, 2007.

OBJECTIVES: For random-digit-dial telephone surveys, the increasing difficulty in contacting eligible households and obtaining their cooperation raises concerns about the potential for nonresponse bias. This report presents an analysis of nonresponse bias in the 2007 National Survey of Children's Health, a module of the State and Local Area Integrated Telephone Survey conducted by the Centers for Disease Control and Prevention's National Center for Health Statistics.
METHODS: An attempt was made to measure bias in six key survey estimates using four different approaches: comparison of response rates for subgroups, use of sampling frame data, study of variation within the existing survey, and comparison of survey estimates with similar estimates from another source.
RESULTS: Even when nonresponse-adjusted survey weights were used, the interviewed population was more likely to live in areas associated with higher levels of home ownership, lower home values, and greater proportions of non-Hispanic white persons when compared with the nonresponding population. Bias was found (although none greater than 3%) in national estimates of the proportion of children in excellent or very good health, those with consistent health insurance coverage, and those with a medical home. However, the level and direction of the bias depended on the approach used to measure it. There was no evidence of significant bias in the proportion of children with preventive medical care visits, those with families who ate daily meals together, or those living in safe neighborhoods.