The Wave I in-home adolescent cohort has been followed up with three subsequent in-home interviews spanning 15 years. In 1996, all adolescents in grades 7 through 11 in Wave I and 12th graders who were part of the sibling pairs subsample were re-interviewed for the Wave II in-home interview (N=14,738, 88.6% response rate), thereby maintaining the integrity and size of the sibling pairs sample. In addition, a follow-up school administrator interview was conducted to measure change in school context from 1995 to 1996. The original Add Health cohort was followed through their transition to adulthood with a Wave III in-home interview in 2001-02 when the sample was aged 18-26 years, and 15,197 original respondents from Wave I were re-interviewed with a 77.4% response rate. In addition, a sample of 1,507 partners of original respondents was also interviewed, filling quota samples of 500 married, 500 cohabiting, and 500 dating partners. Wave IV re-interviewed the original Add Health cohort as they settled into adulthood in 2008-09 when the cohort was aged 24-32 years (N=15,701) with a response rate of 80.3%. For more details on the Add Health design see Harris (2010, 2011).
