United States on socioeconomic variables based on the 2000 Decennial Census. Data were collected in personal interviews, using a computer-assisted survey instrument administered by lay interviewers. All potential respondents were informed in writing about the nature of the survey, the statistical uses of the survey data, the voluntary aspect of their participation and the Federal laws that rigorously provide for the confidentiality of identifiable survey information. Only respondents consenting to participate after receiving this information were interviewed. The research protocol, including informed consent procedures, received full ethical review and approval from the U.S. Census and the U.S. Office of Management and Budget.
