Study Design

Add Health is a school-based, longitudinal study of the health-related behaviors of adolescents and their outcomes in young adulthood. Add Health postulates that families, friends, schools, and communities play roles in the lives of adolescents that may encourage healthy choices or may lead to unhealthy, self-destructive behavior. Data to support or refute this theory are collected from students, parents, school administrators, and others.

Adolescents in Context

As a group, adolescents are healthy people. Threats to their health stem primarily from their behavior. As they direct their energies toward achieving popularity, autonomy from adults, success in school or sports, satisfying romantic and platonic relationships, and confidence in themselves, they make choices that have health consequences.

Waves I and II examine the forces that may influence adolescents' behavior, in particular: personal traits, families, friendships, romantic relationships, peer groups, schools, neighborhoods, and communities. For example, families differ in size, composition, resources, history, and cohesiveness. Some schools comprise a wide variety of students, classes, sports, and special-interest clubs; others provide only limited choices. Some communities offer adolescents many possibilities for interesting, healthful activities; in others, the possibilities for self-destructive behavior predominate.

Many of the choices adolescents make—staying in school or dropping out, getting married or staying single, attending college or getting a job—have consequences that are not apparent until later. As adolescents move toward adulthood, the decisions they made begin to influence the outcomes they experience. Wave III explores the transition between adolescence and young adulthood.

Sources of Data

Beginning with an in-school questionnaire administered to a nationally representative sample of students in grades 7 through 12, the study follows up with a series of in-home interviews of students approximately one, two, and six years later. Because original respondents are re-interviewed, it is possible to measure directly the influence of their experiences at one time on their choices, and at another time on the consequences of those choices. Other sources of data include questionnaires for parents, siblings, fellow students, and school administrators and interviews with partners. Preexisting databases provide information about neighborhoods and communities.

Codebooks and datasets are available for study and provide opportunities to increase knowledge in the social and behavioral sciences and many theoretical traditions. With data from so many sources, new types of analyses are possible, involving both separate and combined effects of factors influencing adolescents' behavior and health status.