The Add Health is a national longitudinal study that explored the influence of social environment on health in adolescence (grades 7 through 12). The first wave of data collection was conducted in 1995 with 20,745 adolescents completing in-home interviews (79% response rate). Of these 20,745 adolescents, 18,255 (88%) were interviewed at Wave II in 1996, and 15,197 (73%) were interviewed at Wave III in 2002. The present study uses the 12,748 respondents who were interviewed at all three waves and have a Wave III sampling weight.
