National_Longitudinal_Study_of_Adolescent_to_Adult_Health
The National Longitudinal Study of Adolescent to Adult Health, also known as Add Health, is a multiwave longitudinal study of adolescents in the United States. It was begun in 1994 in response to a Congressional mandate to study adolescent health, and was initially called the National Longitudinal Study of Adolescent Health.[1] The first wave of the study, funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, involved administering a questionnaire to a nationally representative sample of 7th- through 12th-graders during the 1994-95 school year.[2][3] In the first wave of the study, the questionnaire was administered to about 20,000 adolescents,[4] making it one of the largest longitudinal surveys of adolescents ever conducted.[2] The participants were then re-interviewed in 1996 (wave II), 2001–02 (wave III), and 2008 (wave IV), with a fifth wave of data collection underway since 2016.[2] The first three waves included, among other information, detailed and sensitive interviews, and the 11,500 participants in wave III also provided urine and saliva samples.[2][4]