The National Survey of Children's Health is a national survey that provides a broad range of information about children's health and well-being collected in a manner that allows for comparisons between states and at the national level. Telephone numbers are called at random to identify households with one or more children under 18 years of age. In each household, one child was randomly selected to be the subject of the interview. The survey results are weighted to represent the population of non-institutionalized children aged 0-17 nationally, and in each state. Collection of data for the National Survey of Children's Health is designed to alternate with collection for the National Survey of Children with Special Health Care Needs so that new data are available every 2 years, 4 years for a particular survey.